parametric sweep

HI,

I am working on Piezoresistivity, Boundary currents module and time dependent study. I have given a time dependent pressure load in the form of a square wave on a thin plate. Since I intend to find the response for a number of plates of different thickness, I have used the parametric sweep option. However, I am getting the following error.

" Error in sweep: The following feature has encountered a problem:
The following feature has encountered a problem:
Constraint found for variables in different Segregated groups. Try to merge these groups.
- Feature: Time-Dependent Solver 1 (sol1/t1)"

Can someone help me out with this error?

Thank you in advance!