Alas poor Google Earth Extension! I knew him well.
The Google Earth Extension for AutoCAD is no longer available on Autodesk Labs. We are aware of the importance of creating kmz/kml files as well as including preliminary surface and aerial imagery in your design workflows and are actively researching possible solutions. At this time we cannot share information about potential future product enhancements. When appropriate, we will communicate technology plans via various channels including Autodesk Labs, Facebook, Blogs and our Discussion Groups.
Hamlet is alive in the lab.