These links provide additional information on GPIB-PCII/IIA board. I'm facing the same problem but I don't want to part away with the boards yet so I continue to use them with Windows 95.
http://digital.ni.com/public.nsf/3efedde4322fef19862567740067f3cc/2499c1cf1322e98e8625659500026d0b?OpenDocument
http://www.ni.com/support/gpib/versions.htm