did you add the support path as suggested?
1. In the Civil 3D command line, type OPTIONS and hit Enter.
2. On the Files tab, expand the Support File Search Path.
3. Add the path C:\program files\autodesk\autocad 2015\map\support\en-us and hit OK.
4. Exit and relaunch AutoCAD Civil 3D 2015.
The "Create/Edit Aliases" dialog should appear from now on whenever you call it.
ETA
funny - Just as I post this to you...my C3D crashes with Fatal Error....REVENGE!!!