Pattern along a path dialog not responding?

Attempting to do a pattern along a spline path. The entity to be patterned is just a single line that is perpendicular to the spline and touching it on one end. I'm able to open the dialog, enter in the necessary settings but get no response when clicking either the "OK" or "Preview" buttons. The program is not frozen, simply nothing happens when I attempt to complete the pattern.

Thanks for any help in advance.