Civil 3D to AutoCAD2008

[fillet mignon]

Hey, I have a problem presented to me from a fellow autodesk'er.

He has a file that was created in Civil3D and was saved as a .dwg. When opened in AutoCAD2008 it gives an error message and all the blocks don't transfer. The trees just show up as green squares etc.
Very strange.
Any ideas?

[SLW210]

What's the Error message? Does he have the Object Enablers installed?

[fillet mignon]

Definitely issues with 08 not agreeing with 05.
We worked around it, and yes, it was the object enablers.
Thanks so much!