1. You don't need to create the folder .eteks/sweethome3d/furniture . Install the SH3F file contained in 3DModels-KatorLegaz-1.0.1.zip with the menu Furniture > Import furniture library...

2. A home is a SH3F file. For rooms management, please read http://www.sweethome3d.eu/userGuide.html#drawingRooms or help. Once the walls are drawn, you can create a room with a simple double-click.

3. The color may look different because of the light. Light management isn't perfect in Sweet Home 3D yet. You can change light brightness with 3D view dialog. Read http://www.sweethome3d.eu/userGuide.html#editing3DView

4. Any 3D program may crash. Update the drivers of your video card and save often your document.