iPhone App made using Xcode 3.2.3 does not run on 3.1.3 OS

Programmer Question

I can't figure this out and I thought that someone might run through the same thing.

I have Xcode 3.2.3 (Pre Release with OS 4 beta) and I started to create my application, after the final touches and everything worked ok, I changed the Simulator - 4.0 to Simulator - 3.1.3 (latest iPhone OS) and I could never start my app again :-(

Does anyone know what I should do?

I created a simple Screencast of the problem so everyone can see what I'm writing about.

Thank you for all the help.

Find the answer here