metadata could not be loaded error

When using a gridview and configuring the data source, you get the following when attempting to establish a named connection. "The metadata specified in the connection string could not be loaded. Consider rebuilding the web project to build assemblies that may contain metadata. The following error(s) occured: Unable to load the specified metadata resource"
Version: Microsoft Visual Studio 2010  
Version: 10.0.30319.1  
Microsoft .NET Framework 4.0.30319