I've used the SST-PFB-CLX module a couple of times, but not with Rotork valves specifically.
Can you post a link to the GSD file for that valve ? Maybe an example of an error or diagnostic code given to you by the SST Profibus configuration software ?
What are the LED's on the PFB scanner doing ?
There's a little ladder logic required in the ControlLogix to enable the PFB scanner. Do you have the recommended rungs in there correctly ? Are any other Profibus nodes on your network working correctly ?