Also, when an app crashes like this, it probably produces a CrashReporter log. (This applies when you launch from the Finder, not when you run from the command line in Terminal.) You can use Applications -> Utilities -> Console to view the console.log, where it will tell you that the app crashed and a crash report was logged. Then you can press the Logs button in the toolbar and navigate to ~/Library/Logs -> CrashReporter -> amule.crash.log to see the crash report. In some cases, this will help us figure out where it's crashing and why. (In this case, lionel77 probably knows more about what's going on than I.)