I have the same problem, we are monitoring over 200 printers with snmp (page counters, toner levels, etc).
server version was 1.0.11 and ubuntu server. I don`t remember how all this started, but now when i start the netxmsd, the process quickly (1 - 2 hours) eats up all available memory and swap space, and crashes with the same message in syslog, indicating segfault in libnxsnmp.so
Tried compile new server on freebsd with same db, and results was the same (segfault in ~2 hours). updated server version to newest 1.1.1 - at a glance all worked correctly, but later server crashed anyway:
Jun 8 21:46:02 netxms kernel: pid 37095 (netxmsd), uid 0: exited on signal 11 (core dumped)
I will try to get a crash dump too from 1.0.11 ubuntu server.