What video card are you using? Im going to go ahead and assume the panasonic is a tv and not pc vga monitor, the picture is jumping because it is not synching up to the tv.hsync or vsync is missing,your video card cant output composite signal through the vga port, or the tv doesnt recognize the signal coming from your card.for now anyways, you may be able to get it working if you adjust some settings in catslyst,or nvidia control panel.
plug them both back in and duplicate displays,go into the cards control app,go to displays,make sure you click on the panasonic,look for the refresh rate and resolution settings,set it to 640x480 and 85hz.see if that works.doubt it will,worth a shot.
I could be wrong, tvs and input signals and refresh rates get very complicated to explain.
your best bet would be if your video card has an s-video output, most tvs have an s-video input in the rear.see if yours does.the most ideal card for this kind of display is the hd 4000 series ati videocards. I have a hd4850 running a 27 ssmsung via s-video.
you could always buy a video converter that converts the vga signal to composite.but this isnt recommended.