"Undefined value found" Error when simulating EM-Wave on imported 3D Pyramid

Hey all,

I am trying to simulate the E-Field enhancements on a micro-pyramid structure for which I imported a pyramid with rounded corners from AutoCAD as a .sat file. I set up everything the way I wanted an used the normal mesh size. After the simulation runs for several minutes I receive the error: "Undefined value found - Detail: NaN or Inf found when solving linear system using SOR".
I am sorry but I have absolutely no clue what to change or where to look for to make the simulation running. It would be very important to get this simulation running therefore I would be very thankful if anyone could point out to me what could be the reason for the error. Here is the dropbox link to my file (as 18MB are too large to attach it here):
dl.dropbox.com/u/11950301/3D_pyramid_import_periodic.mph

One thing I could think of is the size of the imported pyramid structure as it is impossible for me to import it in the right dimensions I had to scale it with an empiric value to make it fit into my geometry. Could that be the reason or is there maybe a way to be able to import the .sat file with exact size and dimensions?

Thanks so much for any help with this,
Best Regards,
Max