I imported my current Android Project to Eclipse on my (Mac OS) device via SVN.
The code shows up alright, but Ecipse shows tons of errors (see screenshot) which do not appear on the device I first used – I am not very experienced with Eclipse but I guess some libraries were not imported?
I installed the current JRE(1.7), Eclipse, the Android plugin which also installed the current Android SDK (4.1).
Any clues?!

Place the sdk path in Window->Preference->android.
And then Click apply.
If you already do it. Then right click the project and goto Properties->android->select android version