>ANR0535W Transaction failed for session 1356 for node
>SY00113 (AIX) - insufficient mount points available to
>satisfy the request.
>
>There is NOTHING else running on this TSM server. All 6 drives are online.

Nothing running can itself be an indication of things suspicious...
It may be that TSM tried to acquire one drive after another, but none of
them could be had - which could well be a problem with the library or
network access to it.  You haven't told us your hardware type or what
diagnostic steps you have taken.  An obvious first step, in your AIX system,
is 'errpt -a | less' and look for odd stuff.  Another obvious step is to
perform a manual query or action against the library, as with the 'mtlib'
command or equivalent for your library type, to get status and, if that
works, to try mounting a tape.  Also, try pinging the library from the
TSM server system.  Do 'SHOW LIBRARY' in TSM and check what it thinks the
status of the library and drives are.  Use 'lsdev' and the like to check
the status of the drives.  Stuff like that, to uncover what's awry.

  Richard Sims, BU