Run the app from a console window. In Windows 7, do Start, then type cmd into the "Search programs and files" edit field. cd to the folder and run your app. Any error messages will remain in the console window after your app crashes.
Most toolbox functions are included in the compiled app. The exception are those functions that have substantial user interfaces with them, like imtool. Perhaps you are trying to call something that has a major GUI that you didn't build yourself. Look at the excluded files log to see what they didn't include in your compiled app. If it's not included then it will throw an error when your code tries to run that function.
