Engineering help needed

If it's not solid wood (it does seem unlikely that solid wood would warp from the weight of CDs), you could replace it with inexpensive solid wood. An 8 ft 1X6 or 1X8 at Lowe's is around $10-12. You'd probably need two of those and they'll usually cut it for you in the store. You'd obviously have to stain it or paint it though and it'd be hard to get it to match exactly.