I'm using Mac OS X 10.6.3 (Snow Leopard), previously upgraded from Tiger.
If I try to install an app, the Application Installer runs, but no windows appear.
Here is what shows in .appairinstaller.log:
Starting app install of file:///Users/larry/Downloads/PasspackDesktop_2-1-1.air
UI SWF load is complete
Unpackaging to /private/var/folders/cZ/cZWyAR06FzeqdW75MLtuOE+++TM/TemporaryItems/FlashTmp0
unpackaging is complete
application is bound to side-by-side version 1.0
application is bound to this version of the runtime
app id com.passpack.desktop
pub id 5608783B8287D942A05053A46986E54ED4532229.1
Application located at /Applications/Passpack
Waiting for user confirmation
Retrieving data ...