Thank you for your feedback.
The problem concerning RadProgressArea not working in Safari in MAC is a known issue which is due to Safari browser. The issue is currently in process of investigation and will probably be fixed for one of the next updates of the control. Regarding the problem with progress area in FireFox, it has already been fixed and the fix will be available in Q1 2008 SP1 which is scheduled for the middle of May.
Don't hesitate to contact us if you have other questions.
the Telerik team