AoE II no military production buildings

I'm quite new to AoE still so i was trying to play a single player game with celts when I noticed that I couldn't build any military production buildings in dark age (apart from barracks), I wasn't sure what was going on so i fast tracked to feudal age to see if I could build them there but I couldn't do that either. I'm not sure whether this is a glitch with just my version of the game and if I need to reinstall the game or something. I have a few screen shots but I'm not sure how to add them