If the script author used zlib for print statements, adjusting the verbosity may generate output that gives you warm fuzzy feelings. Lots of examples for you to find if you are the author
Like Darzil, I deal with debugging by adding print statements. Where to put them is an art and the better you know your code the faster you will find out where useful statements go. I often print something at the start and end of loops, for each iteration in a loop and prehaps a variable or two before a decision point (if statement).
If you have enabled stack traces on abort and you mash the stop now button and the stars align you should be told where the script was when it stopped. That may or may not be related to what it was actually doing when you mashed the button but sometimes it will point you in the right direction.