WCF Service errors - Could not load type 'System.Security.Authentication

Same WCF Service works at another environment but got error in my local, er开发者_运维技巧ror message -

Could not load type 'System.Security.Authentication.ExtendedProtection.ExtendedProtectionPolicy' from assembly 'System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'.

I checked much info, for example - http://code.msdn.microsoft.com/KB975954/Release/ProjectReleases.aspx?ReleaseId=3839 tried to uninstall KB976769v2. reboot, but failed tried to install hotfix regarding the same issue, reboot, but still failed.

Please help me out. Thanks in advance.