Please turn on debug logging, so you will know at which line it stops.
Maybe it is due to a bug in LiteSpeed,
Please upgrade to latest build of 5.1.9, check if there is a core file under
/usr/local/lsws/bin/
directory.
forward us the core file along with lshttpd.5.1.9 binary, or, let us login to the server to check the core file.