In case anybody might come across this issue:
I use to have my workspace on a remote network folder and created the exported air package there (Flex 4.5, Air 2.6). When doubleclicking to install the air package when it is still located in the remote folder the installation will fail saying the package is corrupt or damaged.
unfortunately I only got the german error:
"Die Anwendung konnte nicht installiert werden, da die Installationsdatei beschädigt ist. Bitten Sie den Anwendungsautor um eine neue Installationsdatei."
solution:
copy the file to your desktop and you're good to go.
