At this stage I've got no idea if any of those plugins could be causing issues. My best suggestion would be to ask around and see if someone can give you a copy of the vpk that's already had the media.zip put into it - we've tried everything else that I can think of, and if a known good vpk doesn't work then you'd need to address the plugins by turning them off one by one, but it shouldn't be nonpdrm or kubridge at least