Seems that you are not the only one having this issue. There are a lot of questions but not really answers to find using the Google Search. No official statement or explanation seems to be available. The following quote have to be enough for now.
Quote from TheSixthAxis.com (Published 25/05/2012 04:03 PM by tsa staff):
Sony have let us know that they are aware of the matter, are working to get it fixed “as a priority”, say it’s “some users” rather than all affected.
Try to call the PlayStation Support at 800-345-SONY for further details. Or just wait for other replies. Maybe someone else knows more about it.
I have had zip code change a bout a year and a half ago and never updated my location about 3 weeks ago I started getting the Error. I updated my location zip code today and it went away. I live in Coolidge AZ.