Here's the deal: I've been trying to get simple NPCs into HL2DM. After searching around the VERC forums and the VDC, it seems that people have been able to get at least zombies to work fine in MP by copying hl2_gamerules.cpp's InitDefaultAIRelationships function into hl2mp_gamerules.cpp.
Now I was almost certain that this was going to work, but apparently the SDK has changed since have done this, and zombie NPCs still crash my game to desktop a few seconds after I add one in-game with ent_create (or during map load if I try to load a map with existing zombies).
I'm pretty sure the function I copied works fine, I have all the latest zombie models from the EP1 gcf, and my skills.cfg has the proper stuff. I am using VC++2005 Express, if that matters. Any ideas?