SW has
free addons to older autocad programs to allow the importing of newer autocad files. (I did say Solidworks)
http://www.solidworks.com/pages/infofor/DWGseries2.html
The addons I believe are to keep people froim purchasing the new autocad programs. So if you have AC 14 / AC200-2004 get these addons for opening newer AC files in your old software.
Also the link has an editor for Solidworks owners to edit DWG files.
Sorry for the earlier text but to clarify---
A quote from the Solidworks web sight>
What are the requirements for installing DWGgateway?
You must have a valid license of AutoCAD® on your computer. AutoCAD LT® is currently not supported.
Which AutoCAD versions are supported by DWGgateway?
AutoCAD : R14, R2000, R2000i, R2002, R2004, R2005.
[Mechanical and MDT variants - support Open only ]. AutoCAD LT is currently not supported.