This error is produced by the inability of the geometry parsing routine to resolve certain elements in the scene. These are typically very complex (eg: compound curves) or sometimes models imported from other software. 

Possible resolutions:

Option 1: Lower the Triangulation Level from ElumTools Settings (below).

Option 2:  Simplify the calculation by setting materials and/or categories to "Ignore" in Material Mapping.  See this blog post for some additional detail.

Option 3:  Use Filter by View Visibility to remove complex geometry from the calculation.  See this link for instructions.