DVD Drive not reading files

Ive got old DVDs of samples in WAV format that my 25k reads and will open but recently (last 6 months) I cant seem to get it to recognise any sort of new data disc I put in its DVD drive?.....I work around this by just makin MP3/audio cds and loading samples like that but when Ive got a sh*t load of drum hits it would be alot easier to have them all on one DVD.....?

any ideas...like the MPC only recognises certain data files (WAVs not being one of them).........?

Must be something to do with the MP reading the disc cos the sounds work fine on the trusty memory card

this is a shot in the dark, but possibly the reader in the mpc is not a fast enough resolution speed to read the newer dvd's