Delta Terrain Model Crashing

I have been attempting to create a Delta Terrain Model from two existing surfaces.  It crashes every time.  I've gone through most of the exception log, but since I don't know exactly what I'm looking for this hasn't been very helpful.  Are there any "standard" fixes for this problem?  My file is only 5.5MB.  

I'm using Power GEOPAK V8i SS3 version 08.11.09.722.

I've recreated the surfaces a few times; no change.

Thanks,

Frank Boston

Michigan DOT

Design Survey Support