Don't use Backup exec for Oracle, FULL STOP
It will cause you endless issues, I have tried using it for 3 years unsuccessfully.
To be fair though Arcserve also has issues.
I would stick with RMan and just use bexec to backup the flat files there
3rd party apps, in my experience, should not be used with Oracle directly.
RMan's easy to pickup and use, you can either get instruction from oracle direct or use a 3rd party consultancy if you can afford
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