EDIT: From pg 16 of the FAQ:
"There's nothing illogical about a flaming, frost, shock weapon (at least not within any framework that allows weapons to generate energy in the first place), and there's no rule against such weapons (think of the weapons having fiery, frosty, shocking flames)."
Sorry! Guess I should have looked more carefully. Ah well. I guess this just makes this post FYI for a rule I suspect many pp overrule.