Visual Studio Team System 2008 Test Edition - Web Test error

I have been playing around with Visual Studio Team System 2008 - Test Edition for past couple of weeks. It’s a good tool for regression testing, automated testing (we can record macro's) and load testing using IIS (more on this later).

The issue I faced was when I ran web test (macro recording), visual studio would throw this error –

Request failed: Could not run Web test 'Login' on agent 'AGSPC00124': Method not found: 'Void Microsoft.VisualStudio.TestTools.WebTesting.WebTestContext..ctor(System.Collections.Generic.Dictionary`2, Int32, System.String, System.String, Int32, Int32, Microsoft.VisualStudio.TestTools.WebTesting.ValidationLevel)'.

at Microsoft.VisualStudio.TestTools.WebStress.WebTestCaseContext..ctor(WebTestCaseVariation variation, Int32 webTestIteration, Hashtable runContextParameters)
at Microsoft.VisualStudio.TestTools.WebStress.WebTestCaseVariation..ctor(WebTestElement webTestElement, Hashtable runContextParameters)
at Microsoft.VisualStudio.TestTools.WebStress.WebTestElement.CreateVariation(IRunContext runContext)
at Microsoft.VisualStudio.TestTools.WebStress.WebTestRunner.StartupVariation()
at Microsoft.VisualStudio.TestTools.WebStress.WebTestRunner.PlaybackThread()

I could successfully record web tests but could never execute them!

Solution -
The issue was because the web test agent couldn’t reference the Microsoft.VisualStudio.TestTools.WebTesting.WebTestContext correctly. It was resolved when I installed (actually reinstalled) the Visual Studio 2008 SP1 Link. Hope this helps someone.