Comment 4 for bug 636478

Hello Hadmut
Have you verified md5 sums of downloaded images?
Are you runnig VM on a processor that support hardware virtualisation (-v or -vt)?
Can you use testdrive instead?
Thank you for taking the time to report this bug and trying to help make Ubuntu better. However, it seems that you are not using a software package provided by the official Ubuntu repositories. Because of this the Ubuntu project can not support or fix your particular bug. Please report this bug to the provider of the software package. Thanks!

If you are interested in learning more about software repositories and Ubuntu the following pages should be informative:

1. http://www.ubuntu.com/project/about-ubuntu/components - information about Ubuntu repositories
2. https://help.ubuntu.com/community/Repositories - information regarding managing repositories