Are you using Flex Builder 3 beta 2 by any chance?
The picture isn't working for me (gives a HTTP 500 error),
but I'd try downloading and installing the latest version of Flex
Builder 3 beta from the Adobe Labs site. Also, you could try
downloading the latest nightly build of the Flex 3 SDK from Labs.
It sounds like maybe you're using a slightly older version of the
Flex 3 SDK.
It's not expired, just hit "continue
You can alternately enter a license #.
It's an oddly implemented warning panel.
I would have put a button on the bottom that said
"license..." or some such, without having a text
field visible, and put larger text saying "89 days