Jason is correct. For the most part, SolidWorks does not do well when attempting to mate edges, it's almost always better to select faces when adding mates if possible.
I'm not real sure what your two parts look like exactly but sometimes you can turn on temp axis and use them to mate parts also. Also you can turn on sketchs and use them to mate and them turn the sketchs back off.
The edge you picked on the disk is not cyclindrical "For Solidworks"
Maybe use the face.