If you install Adobe Air 2 on an amd64 ubuntu 10.04 (or any other debian based amd64) , you’ll get some problems.
Some nice guys already wrote something about this problem, like Jeremy Wilkins .
See his post there: http://jerwilkins.posterous.com/installing-latest-adobe-air-on-ubuntu-lucid-1
Now, what they will teach you is to foget about the dpkg / apt way of installing it and it’s a pitty. Adobe made a good work of it, providing dpkg way of deinstalling applications and so.
Here is how to deal with this architecture issue.