Problem: Jumping Picture

I've been noticing this problem for a few weeks. At first I thought it was a problem with TheaterTek until I noticed the same problem when just browsing the net on my TV. Randomly, the picture on my TV will jump or bounce about an inch to the right. It immediately goes right back to the correct position. This usually occurs two or three times while watching a movie. I'm not sure if this is a hardware of software problem. I'm running PowerStrip at 960x540p using Karnis' Nvidia guide over at Digital Connection. Also, it only happens when viewing the HTPC. I've never seen the picture bounce while watching cable.