This is the gnarly situation where a pending I/O operation is blocking.
The best you can do remotely is use TSM and 3494 queries to ascertain where the 
tape seems to be within the process of mounting it.  In some cases, you can jog 
the tape drive at the OS level to cause I/O status to be returned to the host, 
and possibly unblock the TSM operation.  The tape/drive problem will remain, 
however.  In my experience, the most common problem is a tape drive defect 
(vacuum failure, mechanical problem, leader block issue) such that the load 
doesn't complete, and the tape is stuck in the drive.  Performing an unload 
operation (which can be initiated remotely) may get it unstuck: sometimes, a 
tape drive power cycle may be a more severe way of getting it out.  An IBM CE 
is the final recourse in that scenario.

     Richard Sims