Ok, I got everything working.
Rolf, you were spot on, the values were U32, not U16. This is especially funny because every single other value used in the DLL is a U16, but at least it works.
In addition, the DLL call needed to be set to C-convention, not Windows API. Once I got these, everything fell into place. I got all of the functions working in the DLL except one, where the documentation is a bit wierd anyway. The function in itself runs, it just doesn't seem to do anything except mess up the data acquisition.
I'd like to say thanks for the great help I got.
I've been working with LV for about 10 years now (self-taught), but I've never (until recently) interfaced with DLLs (in LabVIEW or any other language). I don't know if that's something good or bad.
Shane.
Using LV 6.1 and 8.2.1 on W2k (SP4) and WXP (SP2)