I have not used a debugger for perl code, but I have used them in the past. Particularly in OO programming, where there are a heirarchy of classes, it is good to step through a particularly troublesome piece of code to see if it is doing what you though it should ("Hmmm - someone is not playing the cards I dealt them").

Several years ago, I developed systems in Gupta's SQL Windows. The built in debugger was powerful - and very useful.