If I understand the information provided correctly, you experience a problem viewing the RadSpell
demos on the Telerik site, yet you are able to use the built-in AJAX spellchecking
capabilities of the RadEditor in the forum.
While the back-end spellchecking engine in both these cases is provided by RadSpell, the client-side is quite different - the RadSpell dialog proper uses a dialog, while the built-in spellchecker uses a spellcheck service, on top of which the editor provides the UI.
That said, there is no known reason why you would not be able to acess the RadSpell demos online. Is it possible that you open a support ticket and send us a screenshot of what you are experiencing, as well as test with different browsers, and/or examine the error consoles of FF and IE for client errors?
Also, letting us know whether you need a RadSpell control by itself in your project, or using the RadEditor with its own spellchecking instead will help us provide you with the best solution.
the Telerik team