I'm having some issues trying to share files between AutoCAD 2000 and AutoCAD LT 2009. Does anyone know if these two versions are compatible?
 

I save a dwg file in 2000, but some parts of the drawing can't be modified in LT 2009 (they can't even be selected).
 
Also, a file saved in LT 2009 can't be opened in 2000. Does anyone know if LT 2009 can save back that far?

 
Sorry for so many questions, this is driving me nuts!