The errors seen in the dsmerror.log were:
07/22/2014 13:27:59 ANS9365E VMware vStorage API error for virtual machine '<vm hostname>'.
TSM function name : visdkCreateVmSnapshotMoRef
TSM file : vmvisdk.cpp (5416)
API return code : 67
API error message : Another task is already in progress.
07/22/2014 13:27:59 ANS5250E An unexpected error was encountered.
TSM function name : vmVddkFullVMPrePareToOpenVMDKs
TSM function : snapshot targetMoRefP is null
TSM return code : 115
TSM file : ..\..\common\vm\vmbackvddk.cpp (12439)
07/22/2014 13:27:59 ANS1228E Sending of object '<vm hostname>' failed.
07/22/2014 13:27:59 ANS4015E Error processing '<vm hostname>': unexpected TSM error (115)
The problem was at the vm level. We found a hung snap vmtools install preventing the snapshot execution.
Resolution: On the vCenter console we manaully stopped the VMtools install and were ableto manually execute a TSM4VE back-up
