One thing you might want to check before you spend any money . Remove the burn tube and push a wire all the way through it . Spiders like to crawl in places like that and build nests. It's happened to me more than once. The last time I couldn't blow it out with 100 psi air. I had to drag the nest out with a piece of wire and clean the tube with a small bottle brush. I put it back together and it worked fine. Be sure to turn the gas bottles off and purge the system (light the stove and let it burn until it goes out by itself) before disassembling anything in the LP system. This may not be your problem because the pilot should still light even with the burn tube blocked, but it's worth a look.
Hope I helped