Recently i played a 1on1 from a while back. As Quicktime starts running all i get is a blank (yet Green) screen with Music playing in the back. Is this happening with anyone else?
Sorry to hear you're having some issues. Unfortunately with technology, this happens from time-to-time. You can file a support ticket here and we'll get you fixed up ASAP. All tickets are replied to within 12 business hours - though it never takes that long.
Alternatively, try using the VLC Player as Daugava suggested. You may also want to try downloading a fresh, clean, new copy of Quicktime Player (free) at www.quicktime.com.