Of course, after posting this, I think I figured it out.

Around here that is considered a very good outcome and one of the reasons we like people to try to reproduce their problem with a small stand alone sample. Trying to isolate the problematic code very often results in an analysis of the code that otherwise is hard to achieve. In fact many monks who have been around here a while (myself included) find that the process of trying to generate a small stand alone script for posting in a SOPW gets the problem solved before the SOPW gets written.

Please though, read ELiSHEVA's node carefully and follow as much of her advice as you can. She offers lots of very good advice that will help improve you code to make it faster and more maintainable.