Hi,
Just to add a bit to the above. If you are running the SQL agent in Backup Exec (BE).
You need to run a full backup within the SQL maint plans, otherwise you get a failed status in the BE backup log, with something to do with "tablespace" i cant remember the exact wording.
Also its best to backup all DBs within SQL.
But take in account you cant backup the transaction log on the Master, Db.
I'm not sure on v7, but on v2000, if you have the option to
"Fix minor problems" enabled on the master db maint plan it will fail.
Paul