Cannot Sweep using Guide Curves

Hello,
I am trying to make a sweep of a squared handle using 4 guide curves. For some reasons Solidworks is not letting me select any of the guide curves. Ive attached some screen shots of the steps i've taken (along with the CAD file). I would really appreciate some help.

Please let me know what i'm doing wrong, or if there is a better way to achieve what i'm looking for.

Thank you!!!

SolidworksParts And Features