No, my vlans are not showing up under the prefixes report. Is the getDeviceData process ongoing, or does it only run once, when nav is started?
getDeviceData is a background process running all the time and is started at the same time as NAV is started. Can you check if the process is actually running?
The file getDeviceData.log will also give some clues as to what data is collected; feel free to send me relevant parts of this file to help with debugging.
Can I also ask, which version of NAV are you using?