Thanks a lot, the FAQ "If this update still doesn't fix your problem, download the file SweetHome3D.l4j.ini, copy it in Sweet Home 3D installation directory (by default it's C:\Program Files\Sweet Home 3D) and relaunch Sweet Home 3D." helped and Sweet Home works fine now.

My fault that I did not ...

I have installed sweet home using first SweetHome3D.jnlp . After unsuccessfull installation I have tried SweetHome3D-3.1-windows.exe file.
Installation process itself into notebook with Intel Core2Duo seems to be OK booth in Win7Prof 64bit as well as Ubuntu 10.10. (dual boot ntbk).

When trying to ...