Cross Video Problems

As you can see from the video, audio waveforms stucks although video is showing (preview and master) correctly. Also, music is playing without any problem.
This is happening all the time and when it is happening Cross is not responding to do nothing untill it comes back to normal.
I don't have any problem when using Cross with audio only.
Also this is from my Win 7 Pro 64bit set up.
Thanks a lot
Stelios, Greece