I am new to OpenStudio/EnergyPlus and Sketchup and am stuck on getting my first "simple" geometry to work. 

I receive the following error.  

RoofCeiling:Detailed="SURFACE 1", Vertex size mismatch between base surface :SURFACE 1 and outside boundary surface: FACE 1  **   ~~~   ** The vertex sizes are 4 for base surface and 5 for outside boundary surface. Please check inputs.

This is where the roof meets the ceiling.  There should be 8 vertices, not 4 or 5.  I created the geometry in FloorspaceJS as I thought it was a simple geometry. I have checked in Sketchup and I can see no problems.  I have even recreated it and made it more simple in the hope that this would help.  It has not made any difference. 

Can anybody advise on what might be the problem?

Thanks