SFCD- 1 PROBLEMS

I have a sonic frontiers cd-1 i've owned for some time now.The player gives great sound but its not reading some of the newer disc i'm buying.The box set from the grateful dead is one that this player wont read all the time.Sometimes i'll put a disc in and it will read it and if i try to go to a certain track it locks the player up.'every disc in the box set will do this' and quite a few others in my collection as well.My older red book cds play fine.DOES anyone know what could be happening.I love this player and i dont want to junk it. Thanks for the help