Did you examine the demo code in more details and if not - have you copied all the code? The "startRequest" and "endRequest" are the IDs of two SPAN elements with different text and they are dynamically shown/hidden by the code you have pasted in your thread. What most probably happens on your side is that you most probably have not copied those SPANs. If you do not need them, you can completely remove that code, otherwise - please add them accordingly.
On a side note when you install RadControls, our online examples projects are automatically installed on your computer and you can not only examine their full source code, but also extend them further in order to meet your requirements.
You can open the demos from here:
Start\Programs\Telerik\RadControls for ASPNET AJAX\Open Sample WebSite In VisualStudio
The actual location on your hard disk is the following one:
C:\Program Files\Telerik\RadControls for ASPNET AJAX \Live Demos
I hope that this information is helpful.
the Telerik team