This seems to be your error message:
2013-08-14T15:58:29.291+03:00 [07908 error 'Default'] class Vmacore::Http::MalformedHeaderException(Server closed connection after 0 response bytes read; , >) 2013-08-14T15:58:47.928+03:00 [11804 error 'HttpConnectionPool-000000'] [ConnectComplete] Connect failed to ; cnx: (null), error: class Vmacore::SystemException(The system cannot find the file specified. ) 2013-08-14T15:58:47.928+03:00 [08148 info 'Default'] ConverterConnection has gone down: The system cannot find the file specified.
0 bytes response usually means the corresponding server has crashed. In your case it is the Converter Worker service. Can you check in Control Panel/Service whether Converter Worker service has stopped working when you get this error message? Can you also provide manually the Converter Worker log file? It should be under %ALLUSERSPROFILE%\Application Data\VMware\VMware vCenter Converter Standalone\logs. You may also want to turn on verbose logging on Converter Worker service. You can find instructions how to do it at http://kb.vmware.com/selfservice/microsites/search.do?cmd=displayKC&docType=kc&externalId=2008019. Remember you need to restart the service after you edit the configuration file.