Sierra Install on GA Z77n, i7 3770k, GT 680 Stuck on Apple logo (black background)

Hi,

I need some help please. I am trying to install Sierra on the system GA Z77n, i7 3770k, GT 680. I booted the installer from a USB pen drive, containing Unibeast/Sierra. After starting Clover installer, it runs for a while and then it gets stuck on a black screen with the Apple logo and some panic message (as shown in the screenshot attached).

I have done some previous installations but never had such problems, so feeling a bit lost. Any suggestion would be greatly appreciated.

Gelson