Mistmatch: effects/balloon_pop/init.lua

Hey, whenever I try to connect to Vent Mob it either blocks me from getting on by telling me some error or I will make it on and then get booted 3 seconds later saying Mistmatch: effects/balloon_pop/init.lua, can anyone help me fix this? I haven’t been able to successfully gotten on. I have all of the valve games and CSS. Help?

remove dismemberment mod