Having the same issues. I have tried everything... still constantly crashing.
***EDIT*** Seems to be an issue when people throw grenades. I tried all the memory allocators that came with the alpha to see if it would fix it, all had the same result when running a custom -malloc= on the dedicated box.
Hopefully a hotfix is released in the next few days, my community and those playing on the server won't let me hear the end of it.