Heh. You typed it correctly when asking the
question about why the command didn't work (it was the first thing I looked for, I even quoted it back in one of my messages), you just didn't type it correctly when actually executing the commands. I missed that bit.
(And looking even closer, I see that you told us the error message said unmount. I missed that bit, too. I only looked closely at the bit where you initially said what commands you had typed.)
Well, I've updated the FAQ entry anyway, so hopefully folks in the future won't make the same mistake. You aren't the only person to have done that.