@Rolfk:
So you're saying (among other things) that "run in any thread" would not make a difference? That it should work (but obviously might "mix" results)?
I thought "run in any thread" had a re-entrant like effect (separate memory space). Haven't given it much thought lately tough. If I understand correctly it only enables parallel execution. That does make more sense.
I guess at least "specify path on diagram" could be tricky, because LV might unload the dll if it's not used anymore? I think LV only unloads dll's when the call library node is called with another path.