Speaker not connecting to Stereo? (97 Jetta)

A few months ago, I bought new front door panel speakers for my car. When I was installing them I realized that my driver side speaker didn't work. I thought it was the old speaker, but when I installed the new speaker, it didn't work either. I then realized that it was one of my wires that were faulty. I then took out my CD stereo system and I didn't see any problems with it there. Somewhere between my speaker and my stereo, I have a problem. I was wondering if anyone could think of maybe where the problem is. If you can then would I be able to fix it myself or should I bring it to someone who deals with this kind of thing.
Thanx.

-Simon