NURBS from autocad to illustrator

[3Dme]

I tried to open a file I drew with autocad in illustrator, but the NURBS I used in Autocad are imported wrong. If I try to export to .eps first, I can get things work, but I'm unable to modify my nurbs later, because they are made of hundreds of little lines then...
Autocad screenshot:

Illustrator screenshot:

 

[3Dme]

I managed to get it work by converting it to a pdf from autocad... nevertheless the problem remains and it's a strange thing...