davenn & kellys_eye have good suggestions for things for you to check. (My kids loved to utilize that trap door for the old VHS tape machines for inserting small toys that I had to remove).
Another possibility is to get a copy of the owners manual, they're usually free on-line, and see if there's something in the menu that might be causing the problem. Another thing I've seen that causes something like this is stuck keys on the unit or the remote (grease/paste from food or whatever). You MAY have a selection key button that's stuck.