the sign-in method you're trying to use isn't allowed for more info, contact your network administrator
Solution (by : Altaf8Jun2010Dubai Airports):
start \run\gpedit.msc
goto computer configuration>windows settings>security settings>local policies>User rights management> Allow log on locally
here you will not be allowed to add any new users (may be only admins can do) but i added the troubling users into one of the group already available and that solved the problem.
