ERROE Asp.net project..........

Question

Error 1 Could not load file or assembly 'System.Data.Services.Design, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' or one of its dependencies. The system cannot find the file specified. C:\Windows\Microsoft.NET\Framework\v4.0.30319\Config\web.config 137