Yesterday I downloaded Windows 7 x64 from MSDN and burned the image on a rewritable disk.
Soon after the welcome screen of the setup it displayed me that the driver of the CD / DVD drive is missing.
First I was wondering how it is possible that I boot from DVD and it can read the DVD but then it displays a message that the driver is missing. It is a little bit strange.

So I tried it once again with the same result.

If solved this problem by installing Window 7 from my USB-Drive.
In order to do so you have to do the following steps:

1. Open the command line (CMD) width administrator rights
2. type Diskpart and press enter
3. type List Disk and press enter
4. type Select Disk ZZ (Replace ZZ with the number which represents your USB Drive) and press enter
5. type clean and press enter
6. type create partition primary and press enter
7. type active and press enter
8. type format fs=fat32 quick and press enter
9. type assign and press enter
10. Just copy all files of your disk to your usb drive
11. Restart and boot from USB

Now you should be able to install it without problems