What version of ArcView are you using? If you are using version 9.2 you can right mouse click on the layer that makes up the DWG, and there should be a tab that is named "LAYERS" you can manipulate the dwg there. If you use the mapexport command, just beware that sometimes this will cause the shapefile that it creates as well as all of the other shapefiles the the target file folder to become corrupted. You'll know if this happens when you get a fatal error when trying to export the shape from autocad. Best of luck.
Currently ArcGIS will not read the 2010 format. ESRI says that they are working on the problem. Anyone working in 2010 will have to save their work back to a previous format for ArcGIS users to bring the dwg into their systems.