This type of error can be so nasty. It took me hours just to resolve it:
Eclipse error – The type android.support.v4.app.TaskStackBuilder$SupportParentable cannot be resolved. It is indirectly referenced from required .class files
The simple solution is not to Copy-Paste the support library in the libs folder of your app but to right click on the project => Android Tools => Add Support Library
And the error is resolved!