Think what you have to do is save the 7.0 file as an ascii then go into notepad and change any references form 7. 0 (or 7.0.1 depending on the version) to 6.5 and it should work.
Or have you tried the FBX exporter?? That might work as it seems to work a lot better between packages that import/export 3d stuff than obj
Hope it helps!
"No pressure, no diamonds" Thomas Carlyle