Here's the log file as requested. The odd thing is the error was logged in the Windows event log at 13:59 but the Converter log (below) has entries before and after this time, but nothing anywhere near this time.
Section for VMware vCenter Converter Standalone, pid=2212, version=5.5.2, build=1890136, option=Release
2014-07-24T10:48:41.205-07:00 [02500 info 'Default'] Logging uses fast path: true
2014-07-24T10:48:41.220-07:00 [02500 info 'Libs'] VThreadBase detected multiple threads.
2014-07-24T10:48:41.220-07:00 [02500 info 'Default'] Handling bora/lib logs with VmaCore facilities
2014-07-24T10:48:41.220-07:00 [02500 info 'Default'] Initialized channel manager
2014-07-24T10:48:41.220-07:00 [02500 info 'Default'] Current working directory: C:\Program Files (x86)\VMware\VMware vCenter Converter Standalone
2014-07-24T10:48:41.220-07:00 [02500 info 'Default'] ThreadPool windowsStackImmediateCommit = true
2014-07-24T10:48:41.220-07:00 [02500 info 'ThreadPool'] Thread pool on asio: Min Io, Max Io, Min Task, Max Task, Max Concurency: 1, 121, 2, 60, 2147483647
2014-07-24T10:48:41.220-07:00 [02500 info 'ThreadPool'] Thread enlisted
2014-07-24T10:48:41.220-07:00 [02500 info 'Default'] Trying converter_server
2014-07-24T10:48:41.220-07:00 [02988 info 'ThreadPool'] Thread enlisted
2014-07-24T10:48:41.220-07:00 [02800 info 'ThreadPool'] Thread enlisted
2014-07-24T10:48:41.220-07:00 [03044 info 'ThreadPool'] Thread enlisted
2014-07-24T10:48:41.501-07:00 [02500 info 'Default'] Trying ufa_agent
2014-07-24T10:48:41.517-07:00 [02500 info 'Default'] [shutdownMgr,25] Ufa shutdown manager registered.
2014-07-24T10:48:41.517-07:00 [02500 info 'Default'] [helper,454] Initializing SSL Contexts
2014-07-24T10:48:45.464-07:00 [02500 info 'Default'] Vmacore::InitSSL: handshakeTimeoutUs = 20000000
2014-07-24T10:48:55.551-07:00 [02500 info 'Default'] [helper,507] Initializing certificates
2014-07-24T10:48:55.778-07:00 [02500 info 'Default'] [task,2069] [LRO] 32 max LROs
2014-07-24T10:48:55.778-07:00 [02500 info 'Default'] [task,2071] [LRO] 6 reserved internal LROs
2014-07-24T10:48:55.778-07:00 [02500 info 'Default'] [task,2073] [LRO] 6 reserved short LROs
2014-07-24T10:48:55.778-07:00 [02500 info 'Default'] [task,2075] [LRO] 12 reserved long LROs
2014-07-24T10:48:55.778-07:00 [02500 info 'Default'] [task,2087] [LRO] 86400-second task lifetime
2014-07-24T10:48:55.801-07:00 [02500 info 'Locale'] Delay loading resources: path (C:\Program Files (x86)\VMware\VMware vCenter Converter Standalone\locale\) locale (en) removeable (false) resmap (015e01b8) extKeys (00000000) (
2014-07-24T10:48:55.801-07:00 [02500 warning 'Locale'] Duplicate key 'hi_IN' in file 'C:\Program Files (x86)\VMware\VMware vCenter Converter Standalone\locale\iso2win.vlcl', only first one is used
2014-07-24T10:48:55.801-07:00 [02500 warning 'Locale'] Duplicate key 'az_AZ' in file 'C:\Program Files (x86)\VMware\VMware vCenter Converter Standalone\locale\iso2win.vlcl', only first one is used
2014-07-24T10:48:55.801-07:00 [02500 warning 'Locale'] Duplicate key 'sr_SP' in file 'C:\Program Files (x86)\VMware\VMware vCenter Converter Standalone\locale\iso2win.vlcl', only first one is used
2014-07-24T10:48:55.801-07:00 [02500 warning 'Locale'] Duplicate key 'az_AZ' in file 'C:\Program Files (x86)\VMware\VMware vCenter Converter Standalone\locale\isodata.vlcl', only first one is used
2014-07-24T10:48:55.801-07:00 [02500 warning 'Locale'] Duplicate key 'sr_SP' in file 'C:\Program Files (x86)\VMware\VMware vCenter Converter Standalone\locale\isodata.vlcl', only first one is used
2014-07-24T10:48:55.801-07:00 [02500 warning 'Locale'] Duplicate key 'uz_UZ' in file 'C:\Program Files (x86)\VMware\VMware vCenter Converter Standalone\locale\isodata.vlcl', only first one is used
2014-07-24T10:48:55.801-07:00 [02500 info 'Locale'] Added locale path C:\Program Files (x86)\VMware\VMware vCenter Converter Standalone\locale\ to locale map
2014-07-24T10:48:55.801-07:00 [02500 info 'Locale'] Delay loading resources: path (C:\Program Files (x86)\VMware\VMware vCenter Converter Standalone\coreLocale\) locale (de) removeable (false) resmap (015e14c8) extKeys (00000000) (
2014-07-24T10:48:55.801-07:00 [02500 info 'Locale'] Delay loading resources: path (C:\Program Files (x86)\VMware\VMware vCenter Converter Standalone\coreLocale\) locale (en) removeable (false) resmap (015e01b8) extKeys (00000000) (
2014-07-24T10:48:55.801-07:00 [02500 info 'Locale'] Delay loading resources: path (C:\Program Files (x86)\VMware\VMware vCenter Converter Standalone\coreLocale\) locale (fr) removeable (false) resmap (015e1518) extKeys (00000000) (
2014-07-24T10:48:55.801-07:00 [02500 info 'Locale'] Delay loading resources: path (C:\Program Files (x86)\VMware\VMware vCenter Converter Standalone\coreLocale\) locale (ja) removeable (false) resmap (015e1568) extKeys (00000000) (
2014-07-24T10:48:55.801-07:00 [02500 info 'Locale'] Delay loading resources: path (C:\Program Files (x86)\VMware\VMware vCenter Converter Standalone\coreLocale\) locale (zh_CN) removeable (false) resmap (015e15b8) extKeys (00000000) (
2014-07-24T10:48:55.801-07:00 [02500 info 'Locale'] Added locale path C:\Program Files (x86)\VMware\VMware vCenter Converter Standalone\coreLocale\ to locale map
2014-07-24T10:48:55.801-07:00 [02500 info 'Locale'] Delay loading resources: path (C:\Program Files (x86)\VMware\VMware vCenter Converter Standalone\vimLocale\) locale (de) removeable (false) resmap (015e14c8) extKeys (00000000) (
2014-07-24T10:48:55.801-07:00 [02500 info 'Locale'] Delay loading resources: path (C:\Program Files (x86)\VMware\VMware vCenter Converter Standalone\vimLocale\) locale (en) removeable (false) resmap (015e01b8) extKeys (00000000) (
2014-07-24T10:48:55.801-07:00 [02500 info 'Locale'] Delay loading resources: path (C:\Program Files (x86)\VMware\VMware vCenter Converter Standalone\vimLocale\) locale (fr) removeable (false) resmap (015e1518) extKeys (00000000) (
2014-07-24T10:48:55.809-07:00 [02500 info 'Locale'] Delay loading resources: path (C:\Program Files (x86)\VMware\VMware vCenter Converter Standalone\vimLocale\) locale (ja) removeable (false) resmap (015e1568) extKeys (00000000) (
2014-07-24T10:48:55.809-07:00 [02500 info 'Locale'] Delay loading resources: path (C:\Program Files (x86)\VMware\VMware vCenter Converter Standalone\vimLocale\) locale (zh_CN) removeable (false) resmap (015e15b8) extKeys (00000000) (
2014-07-24T10:48:55.809-07:00 [02500 info 'Locale'] Added locale path C:\Program Files (x86)\VMware\VMware vCenter Converter Standalone\vimLocale\ to locale map
2014-07-24T10:48:55.809-07:00 [02500 info 'Locale'] Locale subsystem initialized from C:\Program Files (x86)\VMware\VMware vCenter Converter Standalone\locale\ with default locale en.
2014-07-24T10:48:55.809-07:00 [02500 info 'Locale'] LoadResources path (C:\Program Files (x86)\VMware\VMware vCenter Converter Standalone\locale\) locale (en) removeable (false) resMap (015e01b8) extKeys (00000000)
2014-07-24T10:48:55.825-07:00 [02500 info 'Locale'] LoadResources path (C:\Program Files (x86)\VMware\VMware vCenter Converter Standalone\coreLocale\) locale (en) removeable (false) resMap (015e01b8) extKeys (00000000)
2014-07-24T10:48:55.833-07:00 [02500 info 'Locale'] LoadResources path (C:\Program Files (x86)\VMware\VMware vCenter Converter Standalone\vimLocale\) locale (en) removeable (false) resMap (015e01b8) extKeys (00000000)
2014-07-24T10:48:55.840-07:00 [02500 warning 'Locale'] Duplicate key 'LicenseManager.LicenseInfo.vaai.label' in file 'C:\Program Files (x86)\VMware\VMware vCenter Converter Standalone\vimLocale\en/default.vmsg', only first one is used
2014-07-24T10:48:55.840-07:00 [02500 warning 'Locale'] Duplicate key 'LicenseManager.LicenseInfo.vaai.summary' in file 'C:\Program Files (x86)\VMware\VMware vCenter Converter Standalone\vimLocale\en/default.vmsg', only first one is used
2014-07-24T10:48:55.848-07:00 [02500 warning 'Locale'] Duplicate key 'com.vmware.vim.license.Feature.vaai.label' in file 'C:\Program Files (x86)\VMware\VMware vCenter Converter Standalone\vimLocale\en/enum.vmsg', only first one is used
2014-07-24T10:48:55.848-07:00 [02500 warning 'Locale'] Duplicate key 'com.vmware.vim.license.Feature.vaai.summary' in file 'C:\Program Files (x86)\VMware\VMware vCenter Converter Standalone\vimLocale\en/enum.vmsg', only first one is used
2014-07-24T10:48:55.848-07:00 [02500 warning 'Locale'] Duplicate key 'vm.guest.WindowsRegistryManager.RegistryKeyName.RegistryKeyWowBitness.WOWNative.label' in file 'C:\Program Files (x86)\VMware\VMware vCenter Converter Standalone\vimLocale\en/enum.vmsg', only first one is used
2014-07-24T10:48:55.848-07:00 [02500 warning 'Locale'] Duplicate key 'vm.guest.WindowsRegistryManager.RegistryKeyName.RegistryKeyWowBitness.WOWNative.summary' in file 'C:\Program Files (x86)\VMware\VMware vCenter Converter Standalone\vimLocale\en/enum.vmsg', only first one is used
2014-07-24T10:48:55.848-07:00 [02500 warning 'Locale'] Duplicate key 'vm.guest.WindowsRegistryManager.RegistryKeyName.RegistryKeyWowBitness.WOW32.label' in file 'C:\Program Files (x86)\VMware\VMware vCenter Converter Standalone\vimLocale\en/enum.vmsg', only first one is used
2014-07-24T10:48:55.848-07:00 [02500 warning 'Locale'] Duplicate key 'vm.guest.WindowsRegistryManager.RegistryKeyName.RegistryKeyWowBitness.WOW32.summary' in file 'C:\Program Files (x86)\VMware\VMware vCenter Converter Standalone\vimLocale\en/enum.vmsg', only first one is used
2014-07-24T10:48:55.848-07:00 [02500 warning 'Locale'] Duplicate key 'vm.guest.WindowsRegistryManager.RegistryKeyName.RegistryKeyWowBitness.WOW64.label' in file 'C:\Program Files (x86)\VMware\VMware vCenter Converter Standalone\vimLocale\en/enum.vmsg', only first one is used
2014-07-24T10:48:55.848-07:00 [02500 warning 'Locale'] Duplicate key 'vm.guest.WindowsRegistryManager.RegistryKeyName.RegistryKeyWowBitness.WOW64.summary' in file 'C:\Program Files (x86)\VMware\VMware vCenter Converter Standalone\vimLocale\en/enum.vmsg', only first one is used
2014-07-24T10:48:55.848-07:00 [02500 warning 'Locale'] Duplicate key 'vm.GuestInfo.AppStateType.none.summary' in file 'C:\Program Files (x86)\VMware\VMware vCenter Converter Standalone\vimLocale\en/enum.vmsg', only first one is used
2014-07-24T10:48:55.848-07:00 [02500 warning 'Locale'] Duplicate key 'vm.GuestInfo.AppStateType.none.summary' in file 'C:\Program Files (x86)\VMware\VMware vCenter Converter Standalone\vimLocale\en/enum.vmsg', only first one is used
2014-07-24T10:48:55.942-07:00 [02500 warning 'Locale'] Key 'Internal.Tasks.SingleSpacedList' in module 'task' under 'C:\Program Files (x86)\VMware\VMware vCenter Converter Standalone\vimLocale\en/' was previously defined; ignored
2014-07-24T10:48:58.092-07:00 [02500 info 'Libs'] [ADS] Local Domain : WORKGROUP
2014-07-24T10:48:58.092-07:00 [02500 info 'Libs'] [ADS] IsWorkgroup: Yes
2014-07-24T10:48:58.092-07:00 [02500 info 'Libs'] [ADS] Local Machine: HOMESRV3
2014-07-24T10:48:58.514-07:00 [02500 info 'Default'] BaseScheduler initialization complete -- void __thiscall Converter::Server::Scheduler::BaseScheduler::Initialize(const class boost::shared_ptr<class Converter::Server::Scheduler::SchedulerEnv>,const class boost::optional<class Converter::Server::Scheduler::SchedulerConstraints const &> &,const class boost::optional<class Converter::VdbConnection &> &) ("d:/build/ob/bora-1890136/bora/sysimage/ufad/server/scheduler/baseScheduler.cpp:112")
2014-07-24T10:48:58.514-07:00 [02500 info 'Default'] Loaded all items from the scheduler's database tables. -- void __thiscall Converter::Server::Scheduler::BaseScheduler::LoadSchedulerItemIdMap(void) ("d:/build/ob/bora-1890136/bora/sysimage/ufad/server/scheduler/baseScheduler.cpp:70")
2014-07-24T10:48:58.514-07:00 [02500 info 'Default'] Loaded all items from scheduler's database tables.Scheduler's item map contains 0 items. -- void __thiscall Converter::Server::Scheduler::PriorityQScheduler::LoadPriorityQ(void) ("d:/build/ob/bora-1890136/bora/sysimage/ufad/server/scheduler/priorityQScheduler.cpp:185")
2014-07-24T10:48:58.514-07:00 [02500 info 'Default'] [plugin,158] ServerPlugin Init
2014-07-24T10:48:58.514-07:00 [02500 info 'Ufa'] Initializing SSL context
2014-07-24T10:48:58.522-07:00 [02500 info 'Ufa'] Plugin initialized
2014-07-24T10:48:58.717-07:00 [04408 info 'ThreadPool'] Thread enlisted
2014-07-24T10:48:58.717-07:00 [04408 info 'Default'] [task,338] [task-internal-1] -- BEGIN -- TaskManager
2014-07-24T10:48:58.717-07:00 [04412 info 'ThreadPool'] Thread enlisted
2014-07-24T10:48:58.717-07:00 [04416 info 'ThreadPool'] Thread enlisted
2014-07-24T10:48:58.717-07:00 [02500 info 'Default'] [plugin,188] ServerPlugin Start
2014-07-24T10:48:58.717-07:00 [02500 info 'Ufa'] SOAP pipe name: \\.\pipe\vmware-converter-server-soap
2014-07-24T10:48:58.717-07:00 [04420 info 'ThreadPool'] Thread enlisted
2014-07-24T10:48:58.717-07:00 [02500 info 'Ufa.HTTPService'] Setting buffer size to 32768
2014-07-24T10:48:58.717-07:00 [02500 info 'Ufa.HTTPService'] Using default for nonChunkingAgents: 'VMware VI Client|VMware-client|VMware-client/3.*'
2014-07-24T10:48:58.717-07:00 [02500 info 'Ufa.HTTPService'] Using default for agentsNeedingContentLength: 'VMware-client'
2014-07-24T10:48:58.717-07:00 [02500 info 'Ufa.HTTPService'] Max buffered response size is 104857600 bytes
2014-07-24T10:48:58.717-07:00 [02500 info 'Ufa'] enableChunkedResponses: true
2014-07-24T10:48:58.717-07:00 [02500 info 'Ufa.HTTPService'] Http Service started: <server p:0x01529da8, '\\.\pipe\vmware-converter-server-soap'>
2014-07-24T10:48:58.717-07:00 [02500 info 'Ufa'] Soap (over Named Pipe) started on pipe \\.\pipe\vmware-converter-server-soap. enableRemoteAccess = false, nonRootAccess = true, useSSL = false
2014-07-24T10:48:58.717-07:00 [02500 info 'Ufa'] Plugin started
2014-07-24T10:48:58.717-07:00 [02500 info 'Default'] Running on OS: Windows 7 Professional, 64-bit Service Pack 1 (Build 7601); CPUs: 8
2014-07-24T10:48:58.717-07:00 [02500 info 'Default'] [serviceWin32,416] vmware-converter-server service started
2014-07-24T18:10:56.938-07:00 [02988 info 'Libs'] [ADS] Get user name failed: 1332
2014-07-24T18:10:56.938-07:00 [02988 info 'Libs'] [ADS] GetTokenInformation failed: 1312
2014-07-24T18:10:57.164-07:00 [02988 info 'Default'] [user,874] Successfully authenticated user Administrator from this local machine (using pipe)
2014-07-24T22:50:25.270-07:00 [02228 info 'Default'] [shutdownMgr,88] Ufa shutdown manager stopping... first make sure this thread is enlisted.
2014-07-24T22:50:25.270-07:00 [02228 info 'ThreadPool'] Thread enlisted
2014-07-24T22:50:25.270-07:00 [02228 info 'Default'] [shutdownMgr,93] Ufa shutdown manager stopping... Total number of callbacks: 1
2014-07-24T22:50:25.270-07:00 [02228 info 'Default'] [shutdownMgr,105] Ufa shutdown manager stopped
2014-07-24T22:50:25.270-07:00 [02800 info 'ThreadPool'] Thread delisted
2014-07-24T22:50:25.270-07:00 [03044 info 'ThreadPool'] Thread delisted
2014-07-24T22:50:25.270-07:00 [02988 info 'ThreadPool'] Thread delisted
2014-07-24T22:50:25.301-07:00 [04408 info 'Default'] [task,343] [task-internal-1] -- FINISH -- TaskManager
2014-07-24T22:50:25.301-07:00 [04408 info 'ThreadPool'] Thread delisted
2014-07-24T22:50:26.504-07:00 [04412 info 'ThreadPool'] Thread delisted
2014-07-24T22:50:26.504-07:00 [04420 info 'ThreadPool'] Thread delisted
2014-07-24T22:50:26.520-07:00 [02500 info 'Default'] [plugin,212] ServerPlugin WaitStop
2014-07-24T22:50:26.520-07:00 [02500 info 'Ufa'] Plugin stopped
2014-07-24T22:50:26.520-07:00 [02500 info 'ThreadPool'] Thread delisted
2014-07-24T22:50:26.520-07:00 [02464 info 'Default'] [serviceWin32,279] vmware-converter-server service stopped
In Services for VMware VirtualCenter Converter Standalone Agent the option "Allow service to interact with desktop" was not checked. I checked it and stopped and restarted the system.
I'll keep an eye on this over the next few days; also I'll shutdown and reboot the machine a couple times a day.
Thanks for the help.