This is a very peculiar issue. Why the first channel would not work when the third channel does, with the same configuration? It sounds to me like it could be a driver error.
There is nothing in the past regarding this type of occurrence, so I wonder if you could try removing the hardware and software, and try reinstalling. LabVIEW 4.1 first, then the driver (NI-DAQ 5.0 or NI-DAQ 6.6, either one, 6.6 preferably according to README files), then the hardware and let me know what happens.
If it's the same, perhaps we'll have to wipe the computer clean, including the registry. This is possible with MSI Blast that we provide on our website:
I've included documentation below regarding its use. If you decid
e to use it, you must remove everything NI from the system, not just some of it. Then you could try reinstalling.
Let me know if you have any further questions or if this does not resolve your issue.
Thanks again and have a great day!
Applications Engineer - National Instruments