Backup Exec by default will report a failed backup if corrupt files are encountered. Backup Exec also sees open files ie. QuickBooks databases that are open when the backup is running as a corrupt file. If you want to disable this in Backup Exec, go to regedit and modify the following registry entry from 1 to 0: Fail Jobs on Corrupt Files
HKEY_LOCAL_MACHINESOFTWAREVERITASBackup ExecEngineBackup