Hi,
The AE Department at National Instruments is instructed to support up till LabVIEW version 7.0 (three versions previous of the newest version). Unfortunately, most of our resources are devoted to helping customers with newer versions of LabVIEW. However, I am willing to help you out to the best of my knoweldge on LV 5.1.
Is there a way for you to describe when you get the thread error and provide a screenshot to this discussion forum.
Regards,
Nadim Rajabi
Applications Engineering
National Instruments