Why is my CD start/stop when I drive?

I have a Ford Galaxy Ghia 2008, and have a Sony DAB 6000 CD player. My radio works fine when driving and also when u go over bumps, holes and other obstructions. But when I play my CD, it stops (like a CD has been scratched) whenever I go over the slightest of bumps/ditches/holes on road. Please help if this can be fixed or do I need a new CD player alltogether???