There is a utility to take out the 'helpful' U3 autorun feature.
Its called
U3 uninstall
Nice, to the point, and does what it says on the tin.
Better than going in through Disk Director and playing around with things that arent meant to played around with.
Not sure if that is your problem though but no harm in trying it if you don't want the waste of time, space, money, bullshlt U3 feature.