Ni does not officially support Labview 6.0 on XP. NI cannot guarantee it will work since it was not designed and tested for XP, especially with language cross-overs.
You can find a list of products compatible with Windows XP at:
http://digital.ni.com/express.nsf/bycode/winxp
However I would still try to follow the instructions recommended by the first link in similar items .
Regards,
Cyril Bouton
Active LabVIEW Developper