user not getting right click context menu

We have one user that is not getting the right click context menu.  When I open the Customize menu, I can see that the GUI.dgnlib is not being loaded which is where these are held so I believe that is the problem.  I thought it would be simple enough to copy that dgnlib from another machine and put it on his machine but when I search the C drive, for dgnlib that one isn't showing up.  Where in the world is this file stored?