Thanks to Devonair and Senocular for pointing me in the right direction as per porting the Flex 2 Tween classes to AS3 Flash 9.0 Public Alpha…
I think I got the all files moved properly and all references to the mx_internal namespace and unresolvable includes commented out, but on compiling I get (among many others):
[SIZE=1][COLOR=blue]Error C:\Documents and Settings…\Local Settings\Application Data\Adobe\Flash 9 Public Alpha\en\Configuration\Classes\mx\events\TweenEvent.as: Line 11: ActionScript 2.0 class scripts may only define class or interface constructs.[/COLOR][/SIZE]
TweenEvent.as is is imported by Tween.as and was copied from my Flex 2 SDK. Of course, TweenEvent.as probably isn’t AS2!! 
…
What does this error mean in this context?
Alternately, if anyone other than Devonair has actually transmuted the Flex 2.0 Tween class to Flash 9.0 PA and could give me a few more details I’d be grateful…
TIA - wlovin