I used the command like and did NOT give it a datacenter name and it started to work, but then I got (from dsmerror.log) a string of the following errors:
08/12/2011 13:11:34 ANS9365E VMware vStorage API error.
TSM function name : vddksdkWrite
TSM file : vmvddksdk.cpp (2271)
API return code : 16000
API error message : One of the parameters supplied is invalid
08/12/2011 13:11:34 ANS0361I DIAG: ANS1111I VmRestoreExtent(): VixDiskLib_Write FAILURE startSector=2560 sectorSize=512 byteOffset=1310720, rc=-1
08/12/2011 13:11:35 ANS9365E VMware vStorage API error.
TSM function name : vddksdkWrite
TSM file : vmvddksdk.cpp (2271)
API return code : 16000
API error message : One of the parameters supplied is invalid
08/12/2011 13:11:35 ANS0361I DIAG: ANS1111I VmRestoreExtent(): VixDiskLib_Write FAILURE startSector=512 sectorSize=512 byteOffset=262144, rc=-1
I found the solution on the symantec web site. One uses diskpart to make sure the data store you are recovering to is not in read-only mode. See
http://www.symantec.com/business/support/index?page=content&id=TECH125911
Be careful with the various vmware names, 'cause it is VERY fenicky.
I haven't tried the GUI without the datacentre name yet; don't know if it will let me skip fields. But, it's working. (I think. The dsmc output is stuck at 3.07GB, but the I/O monitor shows a lot of activity in the appropriate places.)
It may be too early to say "yeah me".