Unrecognized element 'extendedProtectionPolicy'

"... it appears this is caused by the usage of multiple platforms. It appears that the configuration is only created when consuming the service on my Windows 7 development box, but then not recognized by other platforms such as Windows Server 2003... However due to its staged rollout, it is not fully supported and hence the above errors are generated."

"The fix? Simple for the time being. Just remove the tag and redeploy the configuration."

http://allen-conway-dotnet.blogspot.com/2010/03/dealing-with-unrecognized-element.html