My pc has been having this weird problem that I did not have in the original campaign, in which in the end of a section of interval 3 at the train station right when it is the last bit of the level the game will after the load bar fill crash and show a message saying "Out of Memory". I've tried lowering all settings to minimun and I assure you I can run this game on max. What do I do?

PS: I'm running the expansion at full HD resolution by changing the width and height at the cfg. file.