I noticed that I could not play ANY video file with power-kernel 45 when OC'ed. I found a temporary solution wich I can live with, and that is loading the default clock settings (thus meaning the 250-500-600 CPU values) via this command:

/usr/sbin/kernel-config load default

I have set up this command in an QBW (Queen Beecon Widget) to easily execute this command via the desktop, and I also have widgets for loading the Ideal overclocked CPU settings. if you execute that command, you should be able to view all video files again, if you have the same problem as I have.

Hope that helped