Load test is not Running in Visual Studio 2012 ultimate?

I have created Load test Project, while i try to run the Run the Load Test , it showing The error that "Method 'TestAgentDisconnected' in type 'Microsoft.VisualStudio.TestTools.LoadTest,Version=11.0.0.0,Culture=neutral,publicKeyToken=b03f5f7f11d50a3a' does not have an implementation", how do i solve this error?