I have seen this happen when the vi cannot find the library. If it is a dll, it should be either in the system32 directory or in the same directory as the VI.
Also, this can happen if the call is of the wrong type. If you open the vi, and check the settings for how the call is made, you will see 2 possibilities. One the Functions tab you will see a selection called "Calling Convention" One is stdcall and the other is C. I suggest trying both ways if this is your code you are operating.
The last possibility is that the function is not being called properly and there is a fault internal to the called code. Sometimes, during the error stack rewind, it will make it back to labview code, but not with information that labview can handle. It then gives a generic error message. If all else fails, look for another version of the api that you are using, or make absolutly sure that the parameters you send in are appropriate for the call... for instance you would not send in a 0 for the divisor if it was a divide function.
Good luck,
CyberTazer
Software Systems Engineer
