Exception Message: Could not load file or assembly 'Microsoft.VisualStudio.QualityTools.Common'

Hi. I began to to configure Test Agent to automate tests.

But I have a error message from my build definition:
 

 
 Main error was this:
 

  Exception Message: Could not load file or assembly 'Microsoft.VisualStudio.QualityTools.Common, Version=12.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies. The system cannot find the file specified. (type FileNotFoundException)
Exception Stack Trace:    at Microsoft.TeamFoundation.Lab.Workflow.Activities.ExecuteRemoteTestRun2.TestRunCreation.CreateTestRun(CodeActivityContext context, ITestManagementService testManager, ITestManagementTeamProject project)
   at Microsoft.TeamFoundation.Lab.Workflow.Activities.ExecuteRemoteTestRun2.TestRunCreation.Execute(CodeActivityContext context)
   at System.Activities.CodeActivity`1.InternalExecute(ActivityInstance instance, ActivityExecutor executor, BookmarkManager bookmarkManager)
   at System.Activities.Runtime.ActivityExecutor.ExecuteActivityWorkItem.ExecuteBody(ActivityExecutor executor, BookmarkManager bookmarkManager, Location resultLocation)

If you receive this error, then you need to check a few factors:

• Check GAC in build agent (C:\Windows\Microsoft.NET\assembly\GAC_MSIL)  - if library exist in this path?
• If you installed Visual Studio, check version. It must be Premium or Ultimate.
• Check build template. It must be same version as Build Controller.