This script is a workaround for a known problem exporting Groups from SketchUp into AutoCAD.
The problem is that duplicate group names, or, group names that are different from their Group instance name, are not managed properly during the export process. By removing the group name, a unique name is insured and blocks will not get overwritten during the export process.
This script removes the name for every group in your model, nested or not. After running the script and exporting your model, be sure to either UNDO the Group Name Delete, or, cancel out of your model without saving.
The problem should be fixed by Google in a follow on SketchUp maintenance release. At that time, the script will be updated to alert the user that it is no longer required.
Another script, ProgressBar, is required for this script. In very large models, it could take several seconds for the process to complete. If you have downloaded ProgressBar in the past, there is no need to download it again.