Adobe recently announced the new beta of AIR, and with it comes a
requirement to update your applications.
Your old AIR apps WILL still work though if you install beta 2 over
the top of beta 1; or (better) if you run the beta 1 installer after
you've installed beta 2. The installer 'adds support' for the beta 1
apps to your newer installation rather than causing conflicts. It is
still advisible to migrate your apps at this stage, as support for
beta 1 apps is unlikely to feature in the full public release, when it
comes next year.
Instructions for migrating from beta 1 to beta 2 can be found at
http://labs.adobe.com/wiki/index.php?title=AIR:Migration&redirect=no