I had the same problem as well - here's how to fix:

Change the line reading (in sub start_gui):

$win  = Win32::GUI::Window->new();

to this:

$win  = Win32::GUI::Window->new(-name=>'Main',-text=>'Perl');

Basically, it seems that Win32::GUI::Window::new needs the name and text args, otherwise it crashes.

Cheers! -josiah