Virtual Panel Issue for the Default B-737-400.

I've noticed that the virtual cockpit in the MS B737-400 has an apparent issue. The gauges are all there are readable OK, but the background to the panel that the gauges sit on has lost all of it's definition, it almost looks like something out of FS4 :) . Anyone seen this before? I've made no changes at all to this FS2002 stock a/c, other than add some textures for various repaints (which also means modifying or changing the aircraft.cfg file). Thanks for any help,Bruce.