I'm having the same problem but when shapefiles are created from a CAD drawing then brought directly into Google Earth then I create a shapefile in ArcMap the CAD generated shapefile and the ArcMap shapefile don't line up they are off by 3 feet. I played around with projections an I found that NAD27 works and make s the 2 line up. This caused a lot of problems it would be nice if we could just export directly form state plane and come into the correct place in GE