To answer your question, several. But it doesn't matter, you don't have a fixed gear issue, you have a chainring/bolt/crank issue, the fixed gear portion is irrelevant. Any decent mechanic will be able to help you.

I currently have have 3 off-road fixed bikes setup. I've never had any of these problems and I do all of my own wrenching. I appreciate that you want to learn how to do this yourself, but sometimes that means you need a teacher. You need another set of eyes: whether it's a mechanic at the LBS, a friend or a local rider with more experience.