For anyone who had upgraded to version 1.0 of Adobe AIR and noticed that the billQ AIR App wasn't compatible, the problem is now fixed (sorry it took so long). You can download the newest version of the billQ AIR App from the Widgets Page, or from your Tools page within billQ, and be back in action.
If you are still using Adobe AIR Beta v2 then you can continue using your current version of the billQ AIR App without any problems. But just be aware that should you upgrade to v1.0 of Adobe AIR, you'll also need to upgrade your billQ AIR App too. I'm sure AIR v1.0 is much more stable then Beta 2, so it's worth upgrading anyway.
Version 1.0 of Adobe AIR can be downloaded here. It is also bundled with the updated billQ AIR App.