Ghuss
There are multiple reasons that can cause crashes on these maps. Here's a list and how to test them:
Too many maps in the "usermaps" folder:
Navigate to %localappdata%\Plutonium\storage\iw5\usermaps.
→ Create a new folder and move every map inside it, then try to run a private match on Outpost.
Custom files (camos, etc.):
→ Remove all custom content.
Too many demo files in %localappdata%\Plutonium\storage\iw5\demo (Theater Mode):
→ Clear that folder.
thats all i know about so try 1 by 1