HI.
In short - maybe you have problems with Active Directory.
In more details, please read and follow the instructions here:
How to ask a question:
http://support.microsoft.com/kb/555375
You should also search for more info here:
www.google.com
www.eventid.net
Good Luck
Yizhar Hurwitz
http://yizhar.mvps.org
I indeed searched throght google and other places, but nothing was helpful !
I checked everything and all configurations seems to be OK.
I am still unable to figure out how to solve this problem.