I am new to Sketchup. I currently am trying the free Sketchup 8 on MacOS 10.6. I can read in an object into Sketchup, and run the OBJexporter from the plugin menu, but the message I keep getting is :

Writing textures failed!
Exporting Component: A
Exporting Component: B
etc.
Nothing to export
Exporting geometry to: /Users/eags/Desktop/Untitled.obj
Done.

The .obj file has content, but cannot be read by Vue or Cheetah3D.

Am I missing something?