The error is coming from the Windows guest. RPC is not function correctly.
Before running a job, make sure that the VeeamVssSupport service is not running on the guest VM(s); stop the service manually if it is running.
Troubleshoot RPC Endpoint Mapper errors using Windows Server 2003 Support Tools from the product CD: http://support.microsoft.com/kb/839880
Sometimes this error is caused by a firewall disconnecting the TCP connection between the two machines. Make sure you have configured dynamic port allocation: http://support.microsoft.com/kb/154596