Trying to create an android app with Facebook integration, I've gotten to the part in the docs where you have to generate a key hash file, it specifies to run the following code
keytool -exportcert -alias androiddebugkey -keystore ~/.android/debug.keystore
| openssl sha1 -binary
| openssl base64
Delete your debug certificate under ~/.android/debug.keystore (on Linux and Mac OS X); the directory is something like %USERHOME%/.android on Windows.
The Eclipse plugin should then generate a new certificate when you next try to build a debug package.
Let me know if that works.