Running an ATI HD5450

Running HDMI output to a 37" plasma through an onkyo av reciever (front HDMI input) to watch DVD files and the signal keeps breaking up randomly, tv and sound go blank and it comes back a second later with the 720p input details popup on the screen

Seems fine when running downloaded flv's or avi's

Any ideas what might be causing it?

What length cable run are you using and have you used it fine before on other hardware? I've had this a couple of times when using HDMI out from PC to TV, signal drops tended to be caused by a loose connection at the graphics card end in my case, but if its a long run the cable may not be up to it, or could just be temperamental perhaps.

Interesting, its a 5m cable, has run fine on other hardware

I gave the connection a wiggle at the gfx card end and that seems to have cleared it