I referred to the TestBed test framework that comes with FPE 3.0. The reason I would like a sample inside that framework instead of in something you created, is that if you can reproduce the error in the testbed, it is something wrong with the engine and
not your code. - Also, it is easier to find a problem with the code you created.
Anyway, I compiled your sample and there are a couple of things you should take a look at.
1. The texture you supply is already convex - no need to decompose it.
2. You are doing a lot of work two times. You are creating the texture data array twice and converting it to a vertices array twice. Not really a problem, but no need to clutter your own code with nonsense.
3. You might want to start out creating your game in the TestBed or use the SimpleSamples framework to get the feel of FPE. Once you get the basics working, you can move it to a project of its own. Like you are doing now, you need to convert between physics
and screen coordinates. You can take a look at
Matthews sample on how to do that.