If that doesn't work it's probably a creatureevent or items that is bugged, I used to have the same errors on my server, and this .net framweork thing didn't work a shit,
So my advice to you is to download a new creatrueevent file & items file and replace them with the current ones you have,
Only replace items if you added any custom items lately.
I solved my problem by downloading a new globalevents,items and creatureevents file.
It may also be a command that is bugged, but i doubt it, check it out anyways.
Run your server as administrator.
My server crashed like every x hour, now it doesn't crash at all.