The Toshiba AC100 was commercialized in Japan and in Europe in September 2010. It was the first ARM netbook produced by a big notebook constructor. Sadly, the AC100 didn’t got a lot of success. The reason of its flop was mainly du to the Android 2.x OS that was suited for a netbook use.
To come / A venir
For now, please refer to the Ubuntu official Wiki.
NB : If even after you followed the Wiki, you still have the error message “No tarball found”, flash this kernel in 6th partition.