Hi,
Are you using Backup Exec 11d build 6235, or 7170?
There was a memory leak issue with 6235 but that was resolved by hotfix. That being said, if you're still running the older build, you may want to consider upgrading, and if the issue remains, we can take it from there and if need be, open a case. You can dowload the latest build from the following link:
http://seer.entsupport.symantec.com/docs/287939.htm
Regards,
Scott