I too have the same problem with the same Seagate drive and software version 10d on a Windows 2003 server. My EXTRA tape which I use if I do not have another tape for the backup was first used on 11/16/06 and I tried to last use it on 1/15/07. When I came in, the tape was ejected. The alert said please insert overwritable media in drive. My settings for that tape are OVERWRITABLE, Infinite - Allow Append.
Now when I insert the tape, the drive runs for a few minutes and then ejects the tape. Is there anyway to reuse or reinitialize the tape?
Also, when I insert one of my good tapes (we run a nightly backup), the drive recognizes the tape, but if I go into MEDIA shouldn't I see what tape is currently loaded?
Any suggestions would be greatly appreciated.