Bogus "Upgrade AIR Runtime" messages

I am developing using Flash Builder 4.5.1 on Mac, debugging via USB on a Motorola Xoom.  Every time I run or debug my app on the device, I get the following dialog box:

Upgrade AIR Runtime

Your device has an older version of Adobe AIR installed. Would you like to upgrade it to Adobe AIR 3.1.0.4880?

However, according to the Xoom application settings screen for AIR, version "3.1.0.488" is already installed.  Answering "yes" to the dialog has the same effect as answering "no" -- the app runs, but the next time I run it I get the same prompt.  Is there anyway to get Flash Builder to recognize that the attached device is really running the latest version?  I've tried uninstalling and reinstalling AIR, but the dialog persists.

Thanks!