We have seen this exact same thing in our 3494 library. These tapes are
in limbo because when the library was brought back on line, it didn't see
the tape where it expected to (still in the drive) and has assigned them to
the "manually ejected tape" category of FFFA . In our setup we could see
this using the command "mtlib -l /dev/lmcp0 -qV -Vvolnumber".
  The only way we have found to get it all cleared up is to assign the tape
to catagory FFFB "the Purge catagory" , again using an 'mtlib' command. It
will then disappear from the library's inventory and we are then able to
check it back in.

  Here is the URL of the document and associated links that helped me
through this process.

http://as400bks.rochester.ibm.com/cgi-bin/bookmgr/BookMgr.cmd/BOOKS/EZ30MC00
/5.6.2


Ben