How do I create a progress bar?
What you set as ['#ajax']['progress']['url'] is wrong: It's not the URL for a JavaScript file, but it's the callback path to use to determine how full the progress bar is. The menu callback should return a value that indicates if the operation has been completed, or it is completed at 10%, 20%, 50%, etc. Looking at the code contained in the progress.js file, I notice the value is expected to be between 0 and 100.

As side note, the value passed in ['#ajax']['progress']['message'] should be passed to t().