I’d recommend using ExternalInterface for ALL flash browser communication to write the cookie etc rather than a direct attempt at getURL(javasctipt: …..) as the latest version of the Flash player disables most of this direct javascript calling functionality and I’m sure it will get locked down even further in the ever more stringent security sandboxing…

In regards to Flash in a form issue, here is Adobe’s official take on it (not that great really, but anyhow):

http://kb.adobe.com/selfservice/viewContent.do?externalId=kb400730

Weird that a nested form tag fixes it….

There is also SWFFormFix here:
http://www.teratechnologies.net/stevekamerman/index.php?m=01&y=07&entry=entry070101-033933