I kind of problems that you has.
But i using is MATLAB R2014a 64bit with these toolboxes SimMechanics Link Version 4.4 .
I install SimMechanics Link to MATLAB R2014a and to CAD software.
When the CAD software file ('.xml') transform to Simulink models, the MATLAB error is
same "Undefined function 'smimport' for input arguments of type 'char'" message.
I trying many ways result fail.Finally i completely remove software and del registration number.
And reperfusion Software is not have the message.Successful installation.
I hope to help you.