You can find the IVI Engine 1.83 on http://www.ni.com/ivi/ivi_prod.htm.
This version of IVI Engine is not compliant with the latest IVI specifications. NI has released the IVI Compliance Package (http://digital.ni.com/softlib.nsf/websearch/6A09FEF37D6AFC2786256DBA005B2796?opendocument&node=132060_US)which is based on and is compliant with the latest version of the instrument programming specifications defined by the IVI Foundation.
Regards,
Vesna