Comment 34 for bug 445385

An update to my previous problem report:

The problem most likely is the transparent http proxy at my work that blocks some files (but not all).

When doing a lucid install with the network disconnected everything was OK. But then running
  aptitude update
caused aptitude to get about 12 files, and then stopping while trying to get the 13th file.
Configuring my own proxy made the problem go away.