First Let's make clean on your mess.

1. As normal user (use your favorite file manager):
--Go to folder where you download and extract the SH3D program. Delete
the extracted folder.
--Keep the SweetHome3D-4.4-linux-x64.tgz or SweetHome3D-4.4-linux-x32.tgz. and the AdvancedEditing.sh3p file.
--Open an terminal (console):
--type su
--type your root password
--type mv /root/home/.eteks
--type exit & close the terminal.
2. Right click on SweetHome3D-4.4-linux-x64.tgz and select "Extract here"
3. Open the new extracted folder (SweetHome3D-4.4) and double click on SweetHome3D file. In few seconds SH3D is runing. Close it.
4. NOW you must already have create something like this:
/home/dorin/.eteks/sweethome3d/ (in my case)
/home/lumaja/.eteks/sweethome3d/ (probably in your case)
---You wheel find 3 folders (furniture; langueges; textures) and a file (preferences.xml)
5. Create here an new folder name plugins
6. Copy in this folder the AdvancedEditing.sh3p file
7. Go to SweetHome3D-4.4 folder and double click on SweetHome3D file.