i have that problem too only with model packs 9 & 10 when i shoot i see white squares from gun.
When i install v 1.09 update gun was normally i have one question too
when i save progress of my level and going back in editor it stops i can press buttons but no effect. I need to open task manager and kill proces. That come to me after installation i have fps before and now i installed again and then shows problem
my pc
amd atholn 900MhZ
512 mr-ram
128 mb graphic card
i never before had that problem
sorry for bad english
Superman is exemple of fool who wears underpants over pants, and then that fool plays so he can fly, save world move moon...