CRM 2011 Update Rollup 18 Error

Hi,

We are installing the update rollup 18 for CRM 2011. But we get the below issue. Please help.

Could not load type "Microsoft.Crm.FeatureControlChecker" from assembly "Microsoft.Crm.Admin.AdminService, Version=5.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"

"

Thanks,