Red is right.
Essentially what happens is the cutscene models...while they are almost identical in many ways to the normal models...they include extra flags that as of now noone knows anything about...even me....and modding those files currently will corrupt pretty much the entire game. It has happened to many people before myself included and it is best not to tamper at all with anything with a CS_ in the name due to the fact that cutscene models are what get used during any story mission, side mission that uses cutscenes....any cutscene basicly like the cutscenes for the classes at the start of each class....etc....those models are not the same as the normal ones.
If you do intend on messing around with cutscene stuff...best to backup the ENTIRE game folder to a safe spot because trust me......you will thank yourself later for doing just that because you WILL run into big problems...mark my words.