Basically, I've made a video regarding my zombie spawns glitching. I use risers and when they spawn they either fall under the map, get stuck or just wave there arms about weird.

It's really bugging me as I can't play a normal round.

I also can't see my perks when I load my map, there invisible. They used to work and now they're gone. Please help me as soon as possible!

VIDEO: http://www.youtube.com/watch?v=kcAptElq5zQ&feature=youtu.be