Among other modules, I have an HP E1458A Digital I/O on an HP E1401B Mainframe controlled via MXI-2. The Driver downloaded from the NI site appears to work just fine, MAX sees the module and identifies the address, for some reason the VI's "Getting Started" example application return an error that says "HP E1458A Initialize".
From your desciption above, it seems you have configured your VXI hardware in MAX and that the functions in the driver are working fine on their own. It also seems that your system is all right, because the program is returning the message "HP E1458A Initlize", and not "unable to intitialize".
But if when running one of the examples you are getting an error, I can give you a couple of troubleshooting steps that you could follow: 1) Run the LabVIEW program in highlight execution (turning on the light bulb on the menu of the Block Diagram) and try to find out when is the error being generated. 2) Capture the VISA and VXI calls with NI-Spy while running the example.
Hope this helps,
Claudia Lorente PXI/VXI Specialty Group Applications Engineering http://w ww.ni.com/ask