John;
I found a Knowledge Base about that error you can refer to. The KB, originally, talks about Labview, but, as Labview makes NI-DAQ function calls in the same way any other Software language, you can apply the same concepts when using VB. The link is:
http://ae.natinst.com/operations/ae/public.nsf/fca7838c4500dc10862567a100753500/2d8abbbb8d45ff74862565f6005c8d7b?OpenDocument
and the KB number is 18TAPEY5
in case you prefer to search for it at our home page.
Hope this helps.
Filipe
Applications Engineer
National Instruments