이클립스에서 ADT 설치시 에러 해결

Missing requirement: Android Native Development Tools 20.0.0.v201206242043-391819 (com.android.ide.eclipse.ndk.feature.group 20.0.0.v201206242043-391819) requires 'org.eclipse.cdt.feature.group 0.0.0' but it could not be found 에러

1. Go to Help/"Install New Software..."
2. Click on "Available Sofware Sites"
3. Search "http://download.eclipse.org/releases/indigo and enable it
4. Search "http://download.eclipse.org/tools/cdt/releases/indigo and enable it
5. Come back to Help/"Install New Software..."
6. Check "Contact all update sites during install to find requiered sofware"
7. Install ADT Plugin
8. IT MUST WORK!!!

http://stackoverflow.com/questions/11419858/installing-adt-on-eclipse