Description of problem:
If you try to install F9 via DVD and boot the media, you will be asked, if you
like a media check. If you do so, you will see a error dialog with just
containing "OK" preventing to continue the installation. You have to reboot the
system.

How reproducible:
Always

Steps to Reproduce:
1. Boot the F9 DVD
2. If you are asked for media check, choose "OK"
3. Either do the test or select "Eject Disc"
4. Select "Continue"
  
Actual results:
The disc is ejected. A error dialog with caption "error" and just a "OK" as text
is shown. There is only one button with "OK" on it. If you press the button, the
same procedure happens.

Expected results:
The normal installation is launched.

Additional info:
1. On tty5 there are some messages:
"Running ... /bin/mount -n -t iso9660 -o ro /dev/sr0 /mnt/source
mount: No medium found".
2. The media passed the check.
3. The problem occures on a virtual box vm and a notebook. Might happen on all
systems.

Please tell me how I can provide further information to help identifying and
fixing the bug.