One of the problems with using the DDA (Dreaded DAQ Assistant) instead of learning how to use "10 functions in NI-DAQmx" to handle your Data Acquisition Applications (there's an excellent White Paper from NI that you really should read) is you don't learn how to use DAQmx and if you realy on the DDA, you are liable to "gang aft agley" (as the Scottish LabVIEW enthusiast Robert Burns once remarked).
I'm not sure, but I think the reason you are getting Errors from the DAQ Assistants is that there is no Task/Device defined for them, Had you used the DAQmx functions, and (as the White Paper should show you) wired a constant (which becomes a Task/Channel constant as appropriate) into the first DAQmx function in your chain, and then connected it to your DAQ device by simply clicking on the little downward-pointing Selection triangle, it would open to show available Input devices, and you could select the appropriate one and have the error disappear. Or leave it blank and have an error "No device".
Hmm -- I'm sitting in an airport, and trying to generate a simple example, but LabVIEW isn't cooperating -- it keeps hanging. So I can't gin up a simple demo, and have to go back and say "Look at the NI-DAQmx Timing" section of "Learn 10 functions" (or the DAQmx examples that ship with LabVIEW). Note that the Examples (and, to a certain extent, the "Learn 10 Functions" document) show you a lot more than you need to wire/connect. The key is that if your device is hooked into the PC, and you wire a Task Constant in to the Task/Channel input, when you right-click the Constant, it should expand and show you all the devices it "sees" and let you choose the one you want to use. [I know, I said that in the previous paragraph ...].
Bob Schor
