(unknown)

hi，
  I install pgadmin today, but when I run it, it shows "Unauthorized

The server could not verify that you are authorized to access the URL  
requested. You either supplied the wrong credentials (e.g. a bad  
password), or your browser doesn't understand how to supply the  
credentials required.?"
    what is the problom?
    could you please help me figure out?
thanks a lot