DAE files are now ok. I completely deleted the source file in Wings3D that was making problems and remodeled some of my furniture from scratch, and now the exported DAE file is fine.

Here is a link however to an archive containing an OBJ and a 3DS file which do not "work":
http://expirebox.com/download/91f5a94c8 ... 68575.html
(OBJ cannot be loaded at all and materials in 3DS are incorrect).