L4D2 server crash

[kkw]

My server alaways crash , here is the message pop-up while crash

Engine error
CLagCompensationManager:StartLagCompensation with NULL CUSERCmd!!!

[CentralFrag]

After a quick Google search it appears to be a SourceMod plugin error. I'd suggest removing a plugin one by one until it stops crashing that way you know what to remove/update.