You can also try to debug the install process by switching to the virtual terminal that shows the kernel log. I think that vt4 shows the kernel log on the debian installation cd. To see it, hit alt+F4. If it isn't there, try other alt+Fx combinations (I think only F1-F5 are working on the install cd). To get back to the install screen, hit alt+F5 (again, I am not sure if it is F5 or something else. If it isn't, try another Fx key).
If you see any strange message there, tell us.