uhmmm in this case probably it's good to remove the vsay command from the server.
at the moment I no longer remember all the various problems in CoD generated by q3msgboom (it's passed a lot of time and the q3 engine is used by so much games that for me is impossible to remember all the effects for each one of them) and in this moment I can't do additional tests on this specific game, so try to disable the vsay* commands (used by q3msgboom) and check if something changes:
http://aluigi.org/patches/q3lamefix.txt
if this works try also to substituite the vsay in q3msgboom.cfg with other commands like "tell" and check the effects on the server and (if you can) also on the clients since is possible that the server doesn't crash but the clients get disconnected