In Google Earth I "Save Place As..." contours.kml. I use your tool Extensions > KML Tools > Import KML File to import it into sketchup, it says "The model does not contain a Google Earth terrain. Do you want to import one first?". I click the "No" button.

Then it says "File seems not to exist. Please check that the file path does not contain Unicode characters. This is a limitation of SketchUp and its Ruby version."

Suggestions?