[HELP] Weapons and models showing black

[N0tiC]

I've been working on a project for about 4 days and I'm right now on the GUI and Weapon Models...
I gotta say that It all worked fine untill "obviously" something went wrong.. I' Modified a .vtf and the game then looked like this..




Remove it, Replace it... does not work... still something wrong with the models or something...


Is this a known issue?
Is there anyone who has a fix for this, or suggestion?

Thanks in advance for your help, N0tiC^

(Not sure if its the right place on the forum... but anyway, I need help...)