BTW are there any restrictions on the use of flash for commercial purposes such as demos? Do I need to pay anything?

The FAQ is confusing in that regard:

Can I use the File Format Specification to create a Flash Video encoder or a Flash Video streaming service?

No, the File Format Specification is provided for the specific purpose of enabling software applications to export to the Macromedia Flash File Format (SWF).

http://www.adobe.com/licensing/developer/fileformat/faq/#item-1-9

They say it's free for business or personal use. That exerpt from the FAQ seems to be about making a derivative program for making SWFs.

But that's what this program is.