Video issues since updating to Lion

Since upgrading both my Macbook Pro and my Mac Mini to Lion I am unable to play any movies, clips, and/or video that is located on the Mini from my Macbook Pro. The flie opens in QuickTime but the only thing I get is sound.

Another problem is, when I access my Mini from my Macbook Pro using logmein, they connect, but I am unable to see anything. I just get a black screen. I know they are connected because I see that they are on the Mini, as it shows that the Mini is being accessed from outside. Can anyone help?