SRTM Error in Elk2 - the type initializer for 'OSGEO.GDAL.GdalPINVOKE' threw an exception

Hi, 

I'm enjoying Elk2 very much, but having some issues getting the topo to work with the large img files. I'm getting the following error with both the 1 arc second and 1/3 arc second files:  "the type initializer for 'OSGEO.GDAL.GdalPINVOKE' threw an exception"  

I am trying to create a surface for the greater Salt Lake City area- which generates well with the hgt file.  This is quite a bit more than the Mt. Rainier example in the Vimeo tutorial- so I'm wondering if the error may have something to do with the large number of points I'm asking it to make. Ideally, I'd like to get higher resolution than the hgt file so I can fabricate this surface at large scale on a cnc mill. 

Thanks!