Here's some additional info that might be relevant.
I was connecting to the ePO server via a VPN the other night and kept getting my network connection cut off. If I was in the middle of an edit and that happened could that have corrupted the policy file?
(Going through my old messages.)
I never did get into this policy to correct it; had to use the month old backup and re-do all of the work that had been done in the previous month. Made me more careful about making periodic policy backups though.
Just FYI: ePO (4.5 and higher I think) has a Server task action called "Export policies" that you can use to help automate policy backups.
If you ever get this error again, look in the ePO server's orion.log file for details about these errors (possibly enable debug logging for McAfee Support, as needed).