Your posting doesn't say where you looked for the lock file.  In
Solaris, it is documented as being in /opt/tivoli/tsm/server/bin/, as
dsmserv.lock.

Note that a zero-length file can be a consequence of a full file
system at the time of attempted file creation, so check that.  Also
check the mtime timestamp on your lock files relative to the time
that your server started, to corroborate.

   Richard Sims