Script Closes Early

Hello, 
So I have this script that I've used countless times. I made a copy of it and within the copy made a few changes to the code to add some additional options. The issue is that when I run this new script it will sometimes run the entire script as it is supposed to perfectly, but then sometimes it just closes midway through. I've stepped through the program using the script editor and it works perfectly. I can't figure out why its closing early. 
The other odd thing about this is that I've even run the old script file that I've used countless times and even it now is closing early at the same point. It works sometimes and then not others. It's very fustrating and I can't seem to find the cause for this especially since it works in debug mode and correctly sometimes and then not other times.