Hello,
It seems the error occurs while backing up specific doc files. Is the backup in this case, a scheduled backup?
Refer to the following technote, it talks of pst files, but the steps might be helpful:
Title: When backing up .PST files using the Outlook email client with the Backup Exec Agent for Desktop and Laptop Option, it gives the error :"The file is in use by another application. It will be retried."
http://support.veritas.com/docs/276644
In case you have any other doubts regarding this issue, do write back to the forum. However if we do not receive your update within two business days, this post would be marked ‘assumed answered’ and would be moved to ‘answered questions’ pool.
Regards.