Error in loading mesh

Hi all,

I am new to this software. I am hoping to create a 100mm*100mm*100mm cube box with spheres inside the box and then applying confining pressure on all sides.

I have tried to import a mesh created from AutoCad (using other computer and copy back to my own computer) using the fix mesh/surface/stress/servo.
However, some errors are happened and the script is terminated.

Can anyone help with this? I have attached with my script. Many thanks.

Josh