I got that too. Even when i turn off all of my mods, it still red. I wish that the creator just makes it into one mod.

I can't make it into single addon because Valve have limited addon's size.
http://steamcommunity.com/sharedfiles/filedetails/?id=135782335
Read "Campaign's parts conflict with each other".

Each piece has a text file that describes what the file is. THIS is the file that is conflicting and can just be ignored. It isn't used for the actual gameplay. WARNING! As this map pack contains an obligitory texture pack you may have to disable all other visual addons to prevent a crash durring gameplay. Because this pack is so comprehensive in it's content I personally disable every other addon except Back to school maps and texture pack and personally have no issues what so ever with gameplay now. Great job guys =D Might I ask for a list or item type (ie weapons) that are uneffected by your textures because I've gotten attached to some of my HD texture addons =p