I know it's not the best solution security wise (if there is danger of attack that you are leaving yourself vulnerable to in this instance?)... but have you tried turning off DEP for Poser 5? It's possible to disable the protection for particular programs - a search for 'DEP' in Win XP (SR2) help will reveal just how you can do this. I suppose it's down to your 'risk analysis' of potential attack whether or not to attempt this possible fix?