If you're trying to kick off a report on the successful completion of a program that has been scheduled in BO, your best bet is to use a Schedule event. That way BO handles all of the event processing. If you use a custom event, you have to trigger the event in your code.
If you're running a program outside of BO and want to run a report on it's completion, then you should create a file event. For file events, BO registers the presence of the specified file in the specified folder after it has been absent for at least one cycle of the Event Server. It does NOT look at the contents of the file or the date/time stamp. So, if your program takes several minutes to run, it would delete the file when it starts and create it when it finishes.
-Dell