Hello David,
I do not know your version of CVI, but see Known Issues in following document: ftp://ftp.ni.com/support/ivi/icp/2.2/ICPReadme.html
My suggestion, download IVI Compliance Package from NI site and install it.
IVI Compliance Package - http://digital.ni.com/softlib.nsf/websearch/37B496ED7B407C3586256F1600683574?opendocument&node=132060_US
Zdenek