Backup Exec and Microsoft Exchange - "The on-access driver failed to read from file..."

Hello,

Im having the following error appear every night in my event log (about 60-70 times in sucession):

"The on-access driver failed to read from file \TEMP\Backup Exec\IMG2\vdb_2010_07_30_1339_25\priv1."

and

"The on-access driver failed to read from file \TEMP\Backup Exec\IMG2\vdb_2010_07_30_1339_25\pub1.."

The event occurs exactly at the same time when the Backup Exec finishes backing up Microsoft Exchange (2003) - so Backup Exec is obviously locking the file.

I just want to know, where \TEMP\ is so i can add an exclusion in Sophos? I have tried excluding the whole C:\Program FIles\Symantec\Backup Exec\* directory and the problem still occurs.

Any ideas?

Thanks