Data Execution Prevention is stoppin ...

First of all, great game guys, I have the Steam version and play it all the time on my desktop (I play nothing but Fortress :D). However, when I try to start up the game on my laptop, Data Execution Prevention stops it from working immeditately after the initial start up box that says, "HERO ACADEMY" on it in big gold letters. And when I go and try to turn off DEP for Hero Academy, it says that it can't be turned off for Hero Academy and won't let me do it.
 
I have a Toshiba Satellite L305 laptop.
 
Operating system: Windows Vista Home Basic (6.0, Build 6002)
 
BIOS: InsydeH2O Version 1.80
 
Processor: Intel(R) Celeron(R) CPU     900 @ 2.20 Ghz, ~2.2GHz
 
Memory: 1916MB RAM
 
Page File: 1352 used, 2720MB available
 
Graphics: Mobile Intel(R) 4 Series Express Chipset Family, 830 MB memory
 
DirectX Version: DirectX 11
 
I'm currently using Microsoft Security Essentials as my anti-virus program.
 
Is there any way to force DEP off, or work around it so that I can play the game on my laptop? It's the perfect portable game but I'm dissapointed that I can't play it on my laptop.