This issue is solved in 2.6.20-8-generic at least for me (and maybe a bit before, I didn't use the restricted-modules for some days)
-- madwifi can't be loaded during the livecd boot (feisty) https://launchpad.net/bugs/83192 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
