Hey Kent,
There is a low-level troubleshooting utility called "IBIC" that will allow you to specify the device number and then send commands to the device. You will have to know some of the settings of the device (like, "Does it expect the EOI line to terminate strings sent to it, or does it expect a '\n' character?").
Here is a link to getting started with using IBIC. This should get you to where you know that the device is working properly.
Also, here are some other links to Knowledgebase articles on this topic.
Instrument not found when scanning for instruments>
Why does "Scan for instruments tell me that it can't find any instruments?Scott