I downloaded a 3d block off of this site to insert into a 3d drawing i am working in AutoCAD Mech 2004.
Error: dwg is invalid???
 
I am thinking the 3d model is a of a later version of AutoCAD and maybe that is the problem. Not certian.
 
In any case if anyone has a work around or can think of what i am doing wrong would be great to know.
 
Thx.
M Childs

Most likely the issue is that the block was created with a newer version of AutoCAD.Go to the following link and download Autodesk's DWG True View. In that program you can convert the DWG file (the block) to earlier versions of AutoCAD.http://usa.autodesk.com/adsk/servlet/pc/index?id=6703438&siteID=123112Good Luck!!