Hello, GivingTree, and welcome to the Monastery!  I hope your experience here is an enjoyable one.

I'm curious, first of all, as to why you are building a GUI that will rest atop C code, which rests atop Perl; are you intending to write the GUI in C, and call the C code from Perl?  Or do you mean to write the GUI in Perl? (which may be a somewhat daunting task if you're new at Perl, but I guess it's one way to "get your feet wet").

Either way, there are solutions, but you may need to explain a little more exactly which path you're trying to take.  It will also help us to answer your question if you clarify what things you've tried already, if any, and what obstacles you've run into.