I have very recently bough my first DVD player, and a copy of Birdguides DVD Guide to British Birds. The DVD plays OK on my PC, but on the DVD player both the sound and the pictures are erratic, with short gaps most noticeable in the commentary. Other DVDs play OK, so I don't think it is the player that is faulty, nor does the disc appear faulty as it is OK on my PC. Is it a compatability problem, or is there something else I should be aware of?