DXF or DWG files scale up and fill the entire artboard when you open the files in Adobe Illustrator CS2.
The Autocad file was saved with unitless dimensions or was saved out of Unigraphics with mm dimensions.
Solution 1: Upgrade to Illustrator CS4 and input the correct import unit dimensions when opening the file.
Upgrade, and then input the correct unit dimensions in the Artwork Scale dialog box when opening the DXF or DWG file. For upgrade information, see the Adobe website at www.adobe.com/products/illustrator.
To scale the file by 3.93700 percentage when you import it:
1. Open the DXF or DWG file.
2. Select Scale By in the Import Options dialog box and type 3.93700 in Percentage.