The installer of Flex Builder Linux Alpha2 is modified slightly to help people trying it out on 64Bit OS. We need to download 32Bit Eclipse, 32Bit Sun JRE and 32bit Firefox for the installation to go successful.
If you are starting the installer on a 64bit OS - (It shows this OS Check message)

If you launch the installer with 64bit Sun JRE - (it exits with this message)

If you choose 64Bit Eclipse while selecting the eclipse path then it throws the below error and exits.

Also note that you will need to install Flash Player debug player manually by copying the libflashplayer.so file into the downloaded version of 32bit Firefox on your 64bit machine.
If you are starting the installer on a 64bit OS - (It shows this OS Check message)

If you launch the installer with 64bit Sun JRE - (it exits with this message)

If you choose 64Bit Eclipse while selecting the eclipse path then it throws the below error and exits.

Also note that you will need to install Flash Player debug player manually by copying the libflashplayer.so file into the downloaded version of 32bit Firefox on your 64bit machine.