(adsbygoogle = window.adsbygoogle || []).push({}); Hello Everyone.

I have recently tried to mod Call of Duty 4.
I have failed.
I have watched many tutorials and videos on how to mod it, but something keeps happening.
Everytime I copy the Gamesave back over, the game loads correctly and everything, but when I go to click "Play Online" it will load, then the game will quit itself.
Same with split-screen.
I don't know if it has to do with the fact I don't have the disc-based CoD 4 (I downloaded it off PSN) or something else.

Any suggestions or answers to this?