Hello Roland,
please download the gpib driver again (maybe a file is corrupt).
A cutomer get the same error under vista with LV 8.2.1 (see link: http://forums.ni.com/ni/board/message?board.id=170&message.id=243155&requireLogin=False)
For the driver download use the link (the 2.5 driver is the latest driver version):
http://digital.ni.com/softlib.nsf/websearch/cf109c216ef27ef38625722c0074a384
Please check also vista updates (MSI Installer).
Did you tried to install the driver on another vista pc?
Kind regards,
Elmar