Installing Adobe Air on Ubuntu 64bit is a little bit tricky. You have to manually install 32bit files using an utility call “getlibs”.
The full tutorial can be found here.
If you got an error like “Error loading the runtime (libsmime3.so: wrong ELF class: ELFCLASS64)”, issue the command below in the terminal.
sudo ln -s /usr/lib32/libsmime3.so.1d /usr/lib32/libsmime3.so