Comment 7 for bug 318135

bogdan2412: Were you using 8.04 or 8.10, and do you have some wubildr files on the root of your partition? When I used the 8.10 installer, I had to copy files from \ubuntu\winboot to the root of the partition; the Wubi 8.04 installer copied some of those same files to the root of the partition for me, and I was able to skip copying files as you suggested.

Agostino Russo: Running the commands manually worked. At that point, I remembered the "Compatibility Mode" options in Windows, and running both the 8.04 and 8.10 installers in compatibility mode for Windows Vista worked without a hitch, including the 8.10 installer now copying some of the winboot files automatically to the root of the drive. At this point, I'd be willing to bet simply checking for either Vista or Windows 7 and following the same instructions would work.