I’ll get straight to the point.  I’ve been playing Team Fortress 2 with no significant issues since the beta was published via Steam…until recently.  For some reason I was randomly getting crashes when the map changed on a server.  The specific error is as given in the title of this post.  I could not for the life of me figure out what might have changed that would have caused an issue like this (completely forgetting I had recently reinstalled Vista).  Instead of actively searching out a solution I continued restarting the game each time it crashed.  This seems to be a problem of mine, putting a band-aid on the problem rather than researching the cause to find a true solution.  Well it turns out it was actually a problem caused by Windows Vista itself in the way it handles memory allocation. 

This issue actually affects more than just Team Fortress 2, but my exposure to the problem was limited to this game.  The solution is a patch provided by Microsoft which I had installed on my previous instance of Vista, and was the reason I had not experience crashing prior to my reinstall.  Hopefully if you’re reading this you’ve taken the initiative to research your problem rather than trying to do what I did.  I have been running successfully with no crashes since installing the patch.  With that said, install the patch and get back to the game!

Microsoft KB Article 940105 - Virtual address space usage in Windows game development