I agree with an earlier comment by Dan, i.e., just get rid of the try/except/finally blocks altogether. Looking at the code, your try/except/finally blocks aren't adding any value, i.e., you aren't handling any of the errors that could be generated. Why trap an error if you aren't doing anything with it? If you need, or think you need, a try statement; it is best to make them as narrow as possible. Multiple function/method calls and loops, especially when combined, do not make for a narrow scope.
As David points out above, the print statement doesn't do anything within a Script Tool since there is no console. Your current code retrieves the messages from the last geoprocessing tool run (that is what GetMessages does), but the messages aren't returned to the user. Additionally, no errors are returned to the user. Do you really want the user to think the tool succeeded when it didn't?
Script tools pass errors back to the user by default, so you don't need to try to do it manually.
