Why can't I build my structures on Farmville?

So for example the horse paddock requires 10 logs 10 saddles and 10 bridles to build... I have all 30 of the building materials but it doesn't allow me to "use" the part instead it just says "ask for more" where it should say "use". Please need help! Have 100's of wild horses on my farm and they are getting in the way. (This goes for things like cow pastures and stuff as well.)