This error is shown due to the fact that a trial version of our product is used. A message, which tells the user that he is using a trial version, is sent to the control's response (i.e. the response is modified by calls to Response.Write()). This message is sent on random time intervals and sometimes causes errors which break the program. If you refresh the page there should not be any given errors.
Please note that there is not any difference in the functionality between the trial and the full version so if there are no other errors in your source code
, you should not experience problems.
the Telerik team