I've had this problem for a long time now and I really want to make zombie maps. The titel basically explains my problem... When I compile the map I have ticked compile paths and I have pathnodes and I also checked the KVS multiple times... I don't know why this is but please help if you can... 

When the zombies spawn they neither attack or move. I put the zombie one step above the ground so they don't get stuck. They spawn out of thin air and they have to break a window to get in. The planks are outside the window. Yeah thats everything I can say. I've seen on the forums that many people have this problem, but nobody have answered the question or found a solution.

thanks for helping me! 

Do you have a info_volume in your map?

As i told you before. You have the clip ai on your window. That little red brush. If you screenshot your radiant this will prove it.