How can I prevent a green screen when playing DVDs to my digital HD TV set?

Since changing from analogue to a splendid new Panasonic digital HD TV and a Sky+ box, if I play a DVD or a video cassette on my Bush recorder/player, the image always appears against a green background. I have tried every permutation of connecting the scart plugs between the DVD player and TV, even tried, in amateurish curiosity, connecting the scart from the player to the Sky box, run through all the AV modes (? if that's the right term) AV1, AV2...etc. Is my problem unique? Eternal gratitude to any kind soul who can solve this (and a generous pub lunch if you happen to pass through my lovely part of Somerset!)