I recently upgraded my version of vCenter from 4.1 U2 to 5.0, I will eventually upgrade all ESX hosts to ESXi 5 but for now i'm trying to get my VSA to backup my VM's.
The following message appears in the event log during the test backup of a VM:-
The data transfer for the following jobs  is not progressing. MediaAgent module is Waiting to receive data from the client.
Eventually the backup does complete but it takes roughly an hour to backup a single VM using Disk Level backup....anyone else have the same setup and scenario?
The logs also show this message...
1852 1b0 02/17 09:54:53 165164 CVMWareInfo::_MountVM_VCB4() - Failed to Download VMX file [iSCSI Datastore R10 (1)] webservices/webservices.vmx
Any help appreciated :)