I also had this problem. In this case, a reinstall and obviously re entering the username password details resolved it for me.
Macmini Server 2011 i7 Quad Core, OS 10.8.2, Amp Onkyo TX-SR308 USB WD drives 3x2TB TV Samsung Plasma 720pEyeTV Integration There are only 10 kinds of people in this world, those who understand binary, and those who don't.