I often switch up my development machine and try different GNU/Linux distros, and I recently ran into a problem with Eclipse and 64-bit Ubuntu 12.04. After installing eclipse and the Android SDK, I could not get my Android project to run. Eclipse was claiming that /home/myuser/android-sdks/platform-tools/adb did not exist, even though it obviously did upon inspection. It turns out that you need to install some 32-bit libraries in order for Eclipse and adb to play nice on Ubuntu:
sudo apt-get install lib32ncurses5 lib32stdc++6
That should get you up and going.