The problem is at
2014-03-10T18:52:38.022+01:00 [05852 info 'Default'] GetManagedDiskName: Get virtual disk filebacking [WTVNX1_VMFS_15_L] PDC_JNC-DoNotPowerOn/PDC_JNC-DoNotPowerOn.vmdk 2014-03-10T18:52:38.022+01:00 [05852 info 'Default'] GetManagedDiskName: updating nfc port as 902 2014-03-10T18:52:38.022+01:00 [05852 info 'Default'] GetManagedDiskName: get protocol as vpxa-nfcssl 2014-03-10T18:52:38.022+01:00 [05852 warning 'Default'] [Converter::Util::PopulateSslIdDb] Empty thumbprint for host wtesx6.intra.wolftheiss.com 2014-03-10T18:52:38.022+01:00 [05852 info 'Default'] GetManagedDiskName: Get disklib file name as vpxa-nfcssl://[WTVNX1_VMFS_15_L] PDC_JNC-DoNotPowerOn/PDC_JNC-DoNotPowerOn.vmdk@wtesx6.intra.wolftheiss.com:902!52 d5 76 8c 7c 91 fa 29-e4 f7 ed 11 cd e4 1e 81
When trying to open the virtual disk Converter server should provide the SSL thumbprint of the ESX server where the virtual disk file is located, however it provides an empty thumbprint and the opening of the virtual disk file later fails because of SSL errors. Converter server is providing an empty ESX Server thumbprint because it is reading an empty thumbprint from vCenter Server.
The reason why vCenter Server is providing empty thumbprints for ESX hosts is a setting on the vCenter Server. It can be found in vCenter Client under Administration/vCenter Server Settings/SSL settings (in the list on the left). There is a checkbox “vCenter requires verified host SSL certificates”. By default this option is turned on, however most likely in your case it is turned off. When deselected, in general this option means all host in the list below are NOT trusted. As a result when a ticket is issued for such a host, the thumbprint field in the ticked (needed for opening the virtual disk) is not populated. On each line in the list along each not-verified host and thumbprint on the right there is a checkbox for “verifying” the specific host thumbprint. After a host’s thumbprint is “verified” then vCenter starts returning a thumbprint for that host along with the ticket information and conversion should be able to proceed. You need to either deselect the global option, or "verify" each specific ESX server you plan to use as a source or destination of a conversion process.
HTH