the glade2perl scripted needed for gtk perl with glade isn't installed when gtk-perl-glade is emerged. you can fix it by running perl -MCPAN -e "install Glade::PerlRun;" yeah i don't think there's an ebuild for that packaage, so someone would have to write it for it to be fixed.
I'll put it in my list. We'll also be removing the gtk-perl-glade ebuild since it is superfelous now that we can use a pdepend in the glade ebuild itself to call gtk-perl. (the gtk-perl-glade ebuild is a mirror of the gtk-perl ebuild). Will correct as soon as i can, Mike
dev-perl/glade-perl