Sorry to revive an old thread - but we just encountered the same error message while running one of our tests in WebUI Developer R2010.3. Here is the extract from the log:
'8/15/2011 6:28:01 PM' - 'Fail' : 63. radexpander: 'Expand' action.
The control type 'ArtOfTest.WebAii.Silverlight.UI.ToggleButton' does not match the xaml tag 'radtogglebutton'
This test was working fine until our dev team upgraded the test application to the Q2 2011 version of the Telerik controls.
I was wondering if the fix referenced above has been integrated into WebUI Developer? If so, which version?