How do I turn on debugging?

I don't remember. I linked to the answer, if you're interested you might find it.

I figured out what the $Tkx::TRACE=64; wasn't doing anything. I had it before the use Thx line.
Now that I have it in the correct place here is what I see.

pp --gui -o gui2.exe gui2.pl -l C:/Perl/lib/auto/Tcl/tkkid ll -l C:/Perl/lib/auto/Tcl/Tcl.dll -x
Set up gcc environment - 3.4.5 (mingw-vista special r3)
Tkx-1-0.0s-gui2.pl-33: button .b -text {Hello, world} -
command perl::callback Tkx-2-0.0s-gui2.pl-34: pack .b
Tkx-3-3.6s-gui2.pl-32: destroy .
Set up gcc environment - 3.4.5 (mingw-vista special r3)