AutoCAD Map3D functions not working
If you have found that a couple of your Map3D functions aren’t working e.g. MAPTRIM, MAPINSERT, you will need to add a support path in the Options-File Tab-Support File Search Path.
In Options > Files > Support File Search Path, Add the path :
C:\program files\autodesk\autocad 2015\map\support\en-us
Apply and close the dialog box.
Now, close Civil 3D 2015 and restart it.
I believe this should now work.
Type in the 2 commands above to see if the display boxes for those functions actually show up. Once that has been confirmed your Map3D should be right to use as expected.