For some time now I have had trouble with the INDUCTOR_COUPLING element in Multisim. I would place it after placing my inductors then adjust the coupling inductor's settings for the inductors to be coupled and the k constant. Every time I would get a netlist error.
Tonight I found out why: Using INDUCTOR_RATED inductors with INDUCTOR_COUPLING will result in a netlist error. Use a standard inductor instead then modify it from the Properties pane.
Never ever use INDUCTOR_RATED if you plan to couple inductors!