You had some 3rd party packages installed:
rc virtualbox-2.1 2.1.4-42893_Ubuntu_hardy Sun xVM VirtualBox
rc virtualbox-3.0 3.0.12-54655_Ubuntu_hardy Sun VirtualBox
Try purging them first and if that doesn't help manually remove /var/lib/dkms/vboxnetflt.
You had some 3rd party packages installed: Ubuntu_ hardy Sun xVM VirtualBox 54655_Ubuntu_ hardy Sun VirtualBox
rc virtualbox-2.1 2.1.4-42893_
rc virtualbox-3.0 3.0.12-
Try purging them first and if that doesn't help manually remove /var/lib/ dkms/vboxnetflt .