Ok. Según leo en el foro de apple, hay algunas posibles soluciones:
I have had this problem with iTunes 9 a few times. It fixes itself after I restart my laptop, and Cover flow works again.
I had a similar issue. After updating to 9.0.1 I couldn't use coverflow. When I tried to, itunes would shut itself down. I believe the problem lies with directX. I went to the Microsoft website, downloaded the latest directX, and now coverflow works.
What version of DirectX do you have on your PC? Is it 9.0.c or something else?
To check, go "Start > Run", type dxdiag and hit enter. It should give your DirectX version down at the bottom of the "System" tab.
Igual y es cosa de DirectX. O también puedes probar con volver a instalar iTunes.