Hi Archie,
Here are the answers:
1. Agents purchased for 9.1 are not compatible with 10d.
2.Backup Exec 10d does not support Windows Sever 2008/2008 R2, however, it does support windows 2000 and windows 2003 as well.
3.As it doesn't support Windo...
make sure both the tape drives are getting detected in the Windows Device manager, regarding the tapes, not showing up.. run an inventory job on the tape drive and then Backup Exec should start showing the tapes.