Parameter list gives empty sweep

Hello,
I am modeling a system intended to display light scattering off of a particle suspended in a liquid medium. I used Electromagnetic Waves, Frequency Domain (emw) and keep getting the error "The following feature has encountered a problem: Parameter list gives empty sweep - Feature: Parametric 1 (sol1/s1/p1).
What does this mean? Am I required to include a parametric sweep in order to use the pre-made study option? I only intend to model under one set of conditions.

Thanks,
Daniel Frantz