I've never called LabVIEW from VBA. But I do know LabVIEW and I do know VBA.
I see one of two possibilities
1. Either the string for the resource name doesn't work for the VISA resource parameter, or the Enable parameter doesn't like the True.
2. Are there more input controls? Do you need to assign a parameter and a value for every control on the Agilent VI? I don't know. Perhaps the VI just assumes the defaut just like if you didn't put a wire into a subVI.
For #1. Break the code smaller. First just do the VISA resource and comment out the Enable parameter and value. Then try again with the VISA resoure and value commented out and assign the Enable to parameter(0) and value(0).
See if which one or if both of those still trigger the error.
