That's exactly my problem except with building the 2nd hut - i have
1) no builders at all
2) no place for them to learn to build
3) 15 villagers but no sign of the start of the 2nd hut

Is there anyway to teach them to build or do I need to start a new game to go further? I am beyond needing hints - a private message to tell me what to do would be greatly appreciated!