I have searched for hours however I still have no clue what is wrong with my configuration.
My project uses a self-written libray (myLib). This library is compiled to work
You need to compile your library for Intel so the Simulator can use it (which I gather you have done already), and then compile it for ARM, so it can run on the iPhone. Then you have to merge the two libraries. There are different ways to accomplish that, or make it more automatic.
Here are some links to help you:
http://blog.stormyprods.com/2008/11/using-static-libraries-with-iphone-sdk.html http://www.clintharris.net/2009/iphone-app-shared-libraries/