I am trying to install Ubuntu Server to a VirtualBox virtual machine using the 32bit MinimalCD. During the step "Install the base system", I get several warnings from packages that cannot be downloaded, like
EDIT: the actual packages that cannot be downloaded seem to differ from day to day. When I retried today the error popped up for entirely different packages, and the aformentioned packages downloaded fine.
This happens consistently in both the standard and the expert installation. I also tried different archive mirrors (US, GB and BE). All the other packages download fine. The strange thing is that when I retry the same step after it failed, everything passes fine from the second run.
Is this a common problem? Is there any way to avoid this step failing?