unwanted walls upon upload

I have 3 models here. Basically the same thing in 3 different scales. After upload I am noticing 2 interior walls that don't need to be there. I have run these models through the Nettfab cloud repair service with no success in keeping those walls out of the model.

Could someone remove these interior walls or advise me how to do it? I tend to lean toward the cloud repair service since Nettfab itself is still very foreign to me outside of using it to view my designs after they have been run through the cloud service.

I am using Sketchup 14 and would like the fixed files to be in the same format as these are not yet completed. I uploaded early to check wall thickness and to get an approximate price for each.

Here is the third model

Your model has extra lines on faces that are creating faces on top of faces. This shows up in Netfabb as inverted normals 'Red' and holes 'yellow lines'
Shapeways and Netfabb will try to repair this by filling in the holes. You are still left with inverted normals. Basically it is faces on top of faces . The software does not know which face is in or out.

1. This shows inverted faces because of the extra lines.
2. Delete one line to see inside.
3. Delete the internal face.
4/5. Delete the extra lines around the external shape.
6. Redraw first line that was deleted.
7. Pick end face, right click 'Orient faces'

That is just one example of fixing one part of the model. You will need to delete a line and face to see inside so you can determine where the extra lines and faces are.