Hi Ciaran, Eric
This usually happens when there is a mix-up in the registry. you can try this, go to the folder where the documentation is installed, usually this one C:\Program Files\Telerik\RadControls for Silverlight Q2 2009\Documentation if you haven't changed the install path. Then run UnRegisterHelp.bat
and after it finishes run RegisterHelp.bat
. Usually this helps. Let me know if you still have problems.
the Telerik team