Timothy,
The problem is in how you setup your input plane. You have it set to be a modal transverse profile based on waveguide Linear1. When we calculate modes we use the refractive index of the waveguide across the input plane. However in your setup you set the input plane at 0.5 um
InputPlane1.SetPosition 0.5
and your waveguide does not start until 0.75 um so there is no refractive index profile across the input plane and it is causing the script to crash.
Try to find the mode using the form and you will be warned that there is no waveguide.
This error handling has been corrected in the new product and is a 32-bit specific issue now.
Scott