it sounds like you waited too long to solve puzzle 12... generally it's best to complpete 3 certain categories of research and have a stable village of 30 or so before training a master builder... truly only puzzle 1 (sometimes 1&2) needs to be solved to get 12... then you can train your builder with the other building puzzles, there's alot of those. and start with a 14 y/o for the building. that way he/she will live longer. and make sure you have someone on medical duty full time in case your builder gets sick. then google village sim and you should find how to activate puzzle 12.
hope that helps... =)
and you might want to consider setting up a spam account that can't expire like hotmail can... i refer you to www.mail.com that's where i have mine. =)