[L4D2] Random crashes...Help!

[InFaility Ward]

Well as you can read, I have been plagued by random srcds crashes..
I'm hosting a 20 player versus server on my PC and most of the time the crashes seem to occur when the map switches, a couple mins afterwards.

Specs:
Windows 7 Professional 64 bit
AMD Phenom II X4 965 Processor 3.4ghz
4GB RAM
Sourcemod 1.3
Metamod 1.19

server.cfg:
sv_minrate 20000
sv_maxrate 33000
sv_mincmdrate 25
sv_maxcmdrate 40
fps_max 1000


Any ideas?..

[realchamp]

Update your SourceMM version. 1.19 is old?