Interesting situation. Couple different ways to go on troubleshooting.
First, Does the cd seem to skip at all before reject? When you make the selections, does the cd get put in the player then reject the disk? If it does, what happens with the cd? Does it spin at all? make quarter turns, etc? If it is any of those then the optical assembly may be going bad.
If it is something else, I may lean towards looking into the CD mechanism control or the ccc.