Please post the code in small format, (put [ small ] and [ /small ])
I think you are trying to prevent clients from joining the zombie team, correct me if I'm wrong. If that's the case, here's the plugin I wrote for that:
http://forums.alliedmods.net/showthread.php?t=45123
By the way, I'm the admin of "fluffy's Zombie Server [Fast DL]" and I use the plugin above to prevent players from joining the zombie team. My clients sometimes get overflows or buffer overflows, etc. but that is to be expected when you have a few plugins running and also 25 bots in the server. My advice to prevent overflows is to get rid of plugins that send messages to clients.