I did have strict and warnings on, but I didn't really think much of the error message you mentioned since this is my first Perl Tk program. Thanks a bunch for your help, my program is working fine now!

In case people were curious this program checks for students that have similar papers, I grade for a class at the university I go to. Needless to say there has been a big copying problem in the class. It uses the Knuth Morris Pratt algorithm to determine just how similar they are.