Hi,
Did you try all the steps (1-5) that I mentioned?
You'll need to disconnect your dock, then uninstall the Displaylink software, then run the Cleaner Tool, then reboot, then install DisplayLink software v7.5 M0 and then finally reconnect your dock.
This is also mentioned here in the last paragraph:
http://www.displaylink.com/support/ticket.php?id=346
Let me know how you get on.
Thanks,
James