You need to manually create the 'gen' directory in your Android project directory.
For compiling your game, as opposed to the Android Player, make sure you edit the AndroidManifest.xml to set the package to one appropriate for you and your game. It is the fourth line in the file. It should be something like 'com.yourcompany.your_game_name'. All lower case, no spaces.
And change the 'name' value in <yourappdir>.project to be the name of your game without spaces, like 'YourGameName'.
And change the 'app_name' value in res/values/strings.xml to have the same name of your game, but it can include spaces, like 'Your Game Name'.
You need to do all of those steps with Eclipse closed so that it recognizes all the values when building the app.
Cheers,
Ancient Lady