I suggest you to upgrade to the latest RadEditor for MOSS, which now is 5.5.0. It is based on the latest RadEditor 2009.2.701.
In order to get the latest RadEditor you should go to the Downloads section under your account, click on the Visual Studio Extensions, DLLs, Scripts, Source Code, DNN and MOSS wrappers ... link and download the RadEditor for MOSS: (zip, 13 MB) installation. You can see the attached screenshot for more information.
Here is the upgrade instructions article that you will need http://www.telerik.com/help/aspnet-ajax/upgrade-instructions-from-v4-to-v5.html
I hope this helps.
the Telerik team