Yesterday I was trying to install the new beta version of Adobe AIR 1.1 for Linux ..
At first the installation didn’t work for me, it says:

An error occurred while installing Adobe AIR. Installation may not be allowed by your administrator. Please contact your administrator.

After contacting Adobe Support they thankfully put me on the right track with the following steps:

1. If you don’t have the Alpha version of AIR runtime, skip to step 4.
2. Uninstall the Alpha version of AIR runtime:

   $ sudo dpkg -r adobeair-enu
   $ sudo rm -rf $HOME/.adobe/AIR /root/.adobe/AIR /opt/Adobe\ AIR /tmp/FlashTmp*

3. Uninstall all the AIR applications that were installed using the Alpha release using dpkg, or simply just use click the air package for each and choose Uninstall.
4. now you can install the Beta version of AIR runtime:

   $ chmod +x adobeair_linux_b1_091508.bin
   $ ./adobeair_linux_b1_091508.bin

Note: if you get the following message:

The application could not be installed because the AIR file is damaged. Try obtaining a new AIR file from the application author.

That means you did not uninstall all the AIR applications that were installed using the Alpha release.