Recommendations:
1. Purge ALL the repository installed packages related to SH3D (that mean including the configuration files);
2. Manually delete or save in other place [HOME].eteks folder;
3. Extract 7.1.tgz somewhere in your user space NOT in wide system.
In my case I have it in my home.
4. Try to run in terminal (to have some output to share with as):
4.1 SweetHome3D script. If don't work, copy the output in a text file
4.2 SweetHome3D-Java3D-1_5_2 script. Do the same.

If non of this work put here the output and probably someone here could help you more punctually.