Note that the likelihood is that your process quota for 'listserv' is set
too low if LISTSERV is dying with nothing specific in the log.  I'd be
particularly suspicious of this at 0030 given that this is the time when
LISTSERV is processing a lot of things, ie, auto-deletes, daily digests,
log reindexing, etc.  If you have a core file from the most recent crash
a debug traceback will probably indicate that it failed on a call to
malloc() or Alloc() (depending on your unix).  So at any rate you'll want
to check your process memory limits in this case.

If you don't have a core file then you probably also need to jack up the
appropriate system setting (maxcorefilesize, maybe?).  On some systems
the default is ridiculously low and may prevent the system from being
able to write out the core file when LISTSERV crashes.

Nathan