Comment 10 for bug 820306

What I have done is to download initrd.gz and linux from wget http://archive.ubuntu.com/ubuntu/dists/lucid-proposed/main/installer-amd64/current/images/netboot/ubuntu-installer/amd64
Installing with the new images partially solved the issue. The first access to the security mirror uses the right url
/mirror/ubuntu-security/dists/lucid-security/Release
But later, after configuring the installed base packages, and at the same time that the installer shows the text "Updating the list of available packages", the bad url is attempted again
/ubuntu/dists/lucid-security/Release.gpg

The installer syslog is attached, and the lines at the top of the sources.list file on the resulting system are verbatim pasted below, where commented lines show the rigt url for standard packages, and the bad one for security

# deb http://192.168.40.138/repomirror/ubuntu lucid main restricted
# deb http://192.168.40.138/repomirror/ubuntu lucid-updates main restricted
# deb http://192.168.40.2/ubuntu lucid-security main restricted
# See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to
# newer versions of the distribution.