Black screen in Tutorial

NappoZZz

Hello,
I´m playing CF since 3 months, but I made a new account. But i couldn´t do the Tutorial until now (in each acc). Every time in the Thrown Weapon training, I can´t throw the grenade a second time.. when i do this (I tried it 10 times), the screen gets black and the game gets down. So, what can I do? Please help me.
Btw, I´m sorry for my bad english, I´m German.