I think this means that your map is at least one year old, maybe there really are updates? Community maps change often.
If you have map in Mapsource, then you can try to send it again to nuvi.
I was never able to test that kind of problem. My first try would be to load img form nuvi to gmaptool and to refresh img header, this is option on "Write" tab of program, mark checkbox "Refresh header date", leave date fields empty and click "Write all".