i haven't been able to resolve this problem and it looks like have to resort to a forum. let me start  with a run down of the configs, the problem at short, and then a detailed description of the problem...

using backup exec 12
using windows standard 2003
using aofo
running full backups
recently updated
no exchange
just a file and ad server.
using dell powervault for backup device
using 400/800GB lto ultrium 3 data tape cartridge

here's the problem...

we have to switch two tapes in order for a backup to complete. recently the server storage has been exponentially growing because more pdf's are being made. when i switch to the second tape it fails with an unknown error.

here's the problem in detail...

on monday morning i insert mondays tape. the job is scheduled to start at 7pm monday night. on tuesday at 9am the tape is ejected from the tape drive and the job status is " ? loading media"  i insert  the second tape and it runs for sometime, suddenly the tape ejects and the byte count gets set to "0" with the job status displaying " ? loading media."  i insert the second tape back in but it ejects again and the backup gets queued until someone cancels the job. when the job gets canceled the byte count gets set back to where it stopped.  i've looked over the logs and there is an unknown error regarding this issue. please much help would be appreciated!!!

thanks.