I have two websites using your Rad Editor, both are running Telerik UI Version 2014.2.724.35.
Both sites are set up identically and both have been working fine up till today when now on one of the sites when you go into a RadEditor and try and upload an image or a file the toolbar for uploading is greyed out and on inspection of the page I am presented with the error uncaught Sys.InvalidOperationException: Sys.InvalidOperationException: Component 'RadFileExplorer1_ajaxLoadingPanel' was not found.
I can't seem to find a solution to this. I've tried rolling back the version and also using the trial of your newer version and i'm left with the same effect.
Any suggestions would be most welcome.