I have downloaded some maps and put them in the "maps".
But when I start a new game (not online) just a 'free fight' I can play but the other one who i am playing against doesn't start building or anything?!?!

Do I have to activate something?

Can anyone help because I'd like to play some other maps

maybe you have downloaded a multiplayer map,there are 3 types of maps:multiplayer/missions/skirmish
for playing against the AI you need a skirmish map because skirmish AI needs some waypoints/waypaths to work wich(created in WB) the other maps dont have this.

1: you can try to make waypaths yourself in WB (if you downloaded a multiplayer map)
also see==>addin AI 

2:the AI has been scripted wrong on your map in WB then simply remove the waypoins/waypaths and make them yourself by following the tut in de link above

to a moderator:maybe this topic can better be moved to maps and world builder or technical support

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