Fred,
Can you read the value being updated directly from the OPC server? Usually you can just view the values and see if they are updating.
The next thing to check would be to use the shared variable monitor to see if the variables that are bound to the OPC server are updating. It is under Tools >> Shared Variable >> Variable Manager.
Also, when you have the program running, do you get any type of error from reading the shared variable? If you are seeing an error, it would give us a little more insight into what is going on.
Brian Coalson
Software Engineer
National Instruments