1 - What map are you playing on?
2 - Do you have a really slow machine with only a little RAM ?
3 - Are youusing RBv1.0 or the WIP version ?
Reasons -
1 - As far as I understand it, the first time you load a map, it will do the waypointing thingy and this could cause yer machine to lag / not respond. Let it finish this process and thereafter it will be much quicker.
2 - Your PC might not have enough CPY power to control you, your graphics card AND an AI Bot.
3 - If you're using WIP version, maybe try Full release version RB v1.0