I'm seeing similar issues when sites like Youtube. The flash never starts playing and all thumbnails are black. I did notice that if i use Chrome instead of Safari, it doesn't happen as often.
I have no issues like these in ML. However I'm using kext version 1.3.17
No luck…
Also when it sleeps the only way I can wake it is by pressing the power button, then black screen again, i hear the system fan. Then after restarting it I have to reset the bios settings (also with AppleRTC).