I already saw that problem in Sweet Home 3D. This is generally due to some objects placed at unknown coordinates (with NaN values) that prevents from computing a correct point of view. What I would like to know is how such values could happen...

Anyway, you should be able to fix it by yourself this way:
- backup your SH3D file
- edit the Home.xml file it contains with a text editor
- in the Home.xml, remove the lines containing [font=courier new]<observerCamera>[/font] or [font=courier new]<camera>[/font] XML elements with some attributes equal to [font=courier new]NaN[/font]
- replace other [font=courier new]NaN[/font] values by 0
- save the Home.xml file and reintegrate it in the SH3D file

If it doesn't work, or if you feel this is too much for you, just send [url=mailto:[email protected]]me[/url] your file. I'll fix it for you.