Backup exec 12.5 & system restore 8.5 to the same NAS NOT WORKING

Help!!

I a having a problem with a server it is win server 03 running exchange sql and I am backing to a single nas drive.  The data up with backup exec 12.5 with the sql add in and Exchange add in and also using system restore to allow for quick recovery to a virtual pc for disaster recovery.

there is no overlap in the time window of the to jobs but every week or so system restore just fails to run with this message

 

Error EC8F17B7: Cannot create recovery points for job: Drive Backup of  (C:\), Data (E:\). Error EBAB0013: A test that safeguards the integrity of the program failed unexpectedly. CHECK failed, Can::GetSafeFrameFileOffset: .\Can.cpp(321): offset != INVALID_FRAME_INDEX.
Details: 0xEBAB0013
Source: Backup Exec System Recovery

adnd there is plenty of drive space?????

Graham