Cannot run program "/Applications/Adobe Flash Builder 4/sdks/3.5.0_AIR_2.5/bin/adl": error=13, Permission denied
After a couple of hours stuck with this error while trying to build by Flex project in MacOS, I finally got it... The AIR sdk is different for each OS. And I was using a merged flex/air sdk I had from my Windows projects... Duh!
So the solution is, download the AIR sdk that matches your OS and overlay it with the Flex sdk you are using. In your project, change the compiler settings to your new sdk ( ) "et voilá"!