Comment 3 for bug 344277

I experienced this exact problem while trying to install the jaunty beta to an asus 1000HE, from a flash drive of course. Just as the original poster described, ubiquity complains about the flash drive being mounted.

I would like to add that the error message makes no sense. It asks if you would like to have the drive unmounted or not, but the buttons read "go back or continue". But, of course, it shouldn't be trying to unmount the installation media in the first place.