Looks like there's an error:
FILE: FileIO_Unlock on '/vmfs/volumes/NFS-DR1/RM-HQ-SPT/RM-HQ-SPT-2012-01-17_08-02-50/RM-HQ-SPT_1.vmdk' failed: No such file or directory
I would suggest taking a look at your system to ensure there's no performance issues during the backup window or something going on with the VM during the window such as higher than normal workload/etc.
