Hi Festo!
I did some research on this error and found some documentation on it. It is an issue that has come up with both 6.1 and 7.0. I believe it is still an issue with LV 7.1, but not sure. R&D is working on the issue and hopefully it will be corrected in a future release.
For the time being, maybe this link will be useful to you:
http://digital.ni.com/public.nsf/3efedde4322fef19862567740067f3cc/da7fa9c467ba4cc886256e62006deba2?OpenDocument
Hope this helps!
Travis H.
National Instruments
Travis H.
LabVIEW R&D
National Instruments