After a google search
I have been able to find the bug report from Eclipse.
In short:
- It is a problem that arises when using Helios with ADT. As the ADT page on android.com says:
Caution: There are known issues with the ADT plugin running with Eclipse 3.6. Please stay on 3.5 until further notice.
- To fix it, you will have to use Eclipse 3.5 and put your project in a newly created workspace. (If you keep the workspace from Eclipse 3.6, the problem will occur even on Eclipse 3.5.)