Richard - Some things I would look at:

ANR8444E Internal Operation: Library _______ is currently unavailable.
        As seen with a 3494 library.  Possibly, you communicate with the 3494
        over ethernet and either something happened to your /etc/ibmatl.conf or
        the network address specified in the file is no longer valid: it is best
        to specify an IP address rather than a network name, to avoid name
        service and reverse lookup problems.
        Make sure your lmcpd daemon is running.
        Go to the 3494 and make sure that its Library Manager is up, that the
        library is in an Online state, and that the host from which you are
        trying to reach it is still allowed in its LAN Hosts list.
        (You also still have the TSM server option Enable3590Library Yes in
        effect, yes?)

 Richard Sims, BU