Buhban,
apologies for not responding sooner.
There is no code for creating a project reference, rather a selection that you make at design time. If using VB6 go to
Projects>References> select "AutoCAD Map 2000i Release 4.5" as well as "AutoCAD/Object DBX Common 1.0 Type Library".
If they are not available for selection you will need to browse for these files:
AMVbApi.tlb
AXAUTO15.TLB
most likely found in C:\program files\Autocad Map 2000i\
If this does not solve your issue please post back