It's likely a permissions issue if you have an NTFS system. Either your vi's are in an admin folder made private or a portion of the software is trying to access an admin only folder. You'll have to change the security setings to allow others to use the files.
See:
http://digital.ni.com/public.nsf/3efedde4322fef19862567740067f3cc/d95e17dfa38ca8a386256b21007660d0?OpenDocument
or
http://digital.ni.com/public.nsf/3efedde4322fef19862567740067f3cc/7f8c8c8c567d160c86256b2000498379?OpenDocument
or do a search on NI.COM for administrator or NTFS
2006 Ultimate LabVIEW G-eek.