As mentioned in previous blog posts, the beta version of VSTS 2008 SP1 is now available.   In order to implementation the Load Test API enhancements (described here: http://blogs.msdn.com/billbar/pages/load-test-api-enhancements-in-vsts-2008-sp1-beta.aspx) we moved some of the classes that are used to implement the different load test patterns into the LoadTestFramework.dll to make them public and also changed the namespace for these classes.   One consequence of this change is that it introduced a dependency: if you install VSTS 2008 SP1 on the Visual Studio client, then you must also install it on the controller and all agents that are online and connected to that controller.   If you install SP1 on the Visual Studio client and attempt to run a load test against a test rig without SP1 installed, the load test will fail immediately with the status Not Executed in the Test Results window, and if you click on the "Test run error" link in the Test Results window, the error shown will look something like:

Failed to queue test run 'username@MYCONTROLLER 2008-06-13 11:17:28': Object of type 'Microsoft.VisualStudio.TestTools.LoadTesting.LoadTestConstantLoadProfile' cannot be converted to type 'Microsoft.VisualStudio.TestTools.WebStress.WebTestLoadProfile'. 

(The first type listed will vary depending on the type of load pattern used by your load test.)

This dependency exists in the beta version of SP1 and will still exist in the final version of VSTS 2008 SP1.