As you may know, the DWG/DXF importer isn't available in SketchUp 7.1. Please note that this functionality continues to be offered in SketchUp Pro.
For those of you who depend on this feature, you can download this optional plug-in for Windows or Mac that enables the DWG/DXF importer. This plug-in will only be available for a limited time, and it will not be supported in our next major release.
You may also consider downloading the SketchUp Pro trial, which allows you to try all of the features of SketchUp Pro including LayOut and Style Builder. You can learn more about the differences between SketchUp and SketchUp Pro on our site.