Thank you for the provided files and information.
We researched the problem in details and it appears that the issue is not related to RadEditor and its Flash manager, but to a limitation of the browser itself. It seems that the browser restricts the download2.swf
file to access the other swf flash in the server directory, which is the reason for the problem.
You will be able to reproduce the same behavior by testing any other rich text web editors.
Since this is a browser behavior, it will be very hard or even impossible to help you further.
All the best,
the Telerik tea