think that you need to update the SharePoint application's main
web.config file (the one in
C:\Inetpub\wwwroot\wss\VirtualDirectories\port\). Add the
<bindingRedirect> elements there and the editor will load OK. Your bindingRedirect should point from the versions that can not be loaded (126.96.36.199 for RadSpell.Net2 and 7.3.2. for RadEditor.Net2) to the ones that you have.
I hope this helps.
the Telerik team