Problem conversion draft to dxf-file

[Jonathan]

I am working with TopSolid Design 2009 (v6.10.212)
When I open a dxf-file in autocad, created with "save as" Autocad V6.7 dxf in TopSolid;
I got the following problem :
The contour-line of the part has a line who is thicker than the other lines.
How can I solve that problem?

[Peter]

This occur because the dwg/dxf version of original file is undetermine . so the best way is to save the file by down grading/upgrading the version translator until it reach the correct original version file. this will often occur expecially when you are working in dxf mode unlike dwg which is much stable format compare to dxf format the old predecessor format (the earliest 2d format)