Having problems opening the game [error log inside]

Hi GrandPrixGames forum!

I'm encountering some technical issues with my GP4 files lately, causing it not to start anymore. After trying to install a 2012 F1 season mod with ZaZ Tools my game kept crashing, so I deleted it again. However, now my game won't start at all anymore giving a black screen and the error message in this image [i.imgur.com]
So I've tried reinstalling the game several times, tried using the v9.6 patch and opening it with GPxPatch, tried another compatibility mode, and at last tried deleting the f1graphics.cfg file but all to no avail. I also cannot find out how to enable the debug output.
The most frustrating part is that I sent all the files and folders to a friend to check wether it works or not and it was working on his computer (running Windows 10). So are there some kind of hidden files from Zaz Tools/GPxPatch/GP4 Tweakers (All programs I've been using) that might cause GP4 to not start anymore?
Can anyone here help me solve this problem? I'm running on Windows 8.1 and before installing this 2012 mod the game was working fine with GPxPatch and GP4 Tweakers.

Thanks in advance!