hi Saleem,
You should have had an option from dell to purchase a support contract as well. Basically the service account in Backup Exec cant logon to the SQL/MSDE instance that Backup Exec uses to run on. If the job is not failing then I wouldnt worry about it. You can use the beutility and change the database access and add the service account and grant access to the database - it may work.
Thanks
Harry