in reply to Tk Listbox problem
You're calling &changeList before the ListBox is actually rendered (with MainLoop). There is nothing *to* delete when it's running. Same error will be thrown on the insert method.
Also, use eq instead of == when you're comparing strings (e.g. if ($system eq "SNES"))
"A core tenant of the greater Perl philosophy is to trust that the developer knows enough to solve the problem" - Jay Shirley, A case for Catalyst.