On my Mac I installed Eclipse, the SDK and created a new project, then hit build expecting to see my first helloworld app.

I got the error "the project cannot be built until build path errors are fixed".

After going thru all the path-like options in Preferences, I noticed that on the tab "Java Build Path" the "Google APIs [Android 2.2]" option did not have its check box checked.

Checking it made the problem go away.

It works now and I can see the app in the Emulator

Have I not set up my environment correctly? I used all the defaults in Eclipse and the Android SDK.