Wubi Installer Can't Find Metalink

bcbc answered this in comments; here and in related bug reports.

Yes there are two bugs at play and different workarounds required... one for Lubuntu (pad.lv/1043607), and another for Xubuntu/Kubuntu etc. (pad.lv/1067833).

– bcbc Oct 17 '12 at 19:58

Lubuntu workaround (bug 1043607, comment #1):

Use the 12.04 version of Wubi.exe for Lubuntu. You can get it off the Lubuntu 12.04 ISO or download it from here: http://people.canonical.com/~evand/wubi/precise/wubi-r266-signed.exe

Workaround for other official Ubuntu derivatives -- Kubuntu, Xubuntu, Edubuntu, Mythbuntu, Ubuntu Studio, etc. (bug 1067833, comment #1, subject to correction in comment #2):

Download the 12.04.1 desktop CD ISO into the same folder as Wubi.exe (12.04.1).

Disconnect from internet.

Run wubi.exe to install.

Reconnect to internet prior to rebooting.

When 12.10 is released (shortly), then it will work again (for the 12.10 releases) but it will still be broken if you use Wubi.exe for 12.04.1. And PS 12.10 Wubi will no longer support Xubuntu.

– bcbc Oct 17 '12 at 20:03