Alternatively, and without root permissions, you can do this in the home folder per user:
1. Open 'Appearance'
2. Click Install and choose the cursor tar package you downloaded. It should give you a 'Theme Installed Successfully.' Click 'Apply New Theme Now' and exit 'Appearance.'
3. Open your home folder and create a folder called 'default' in the folder /home/YOUR_USERID/.icons/
4. Go into the folder you just created and right click and create an empty file here. Open the file with gedit and past the line from the tip above '[Icon Theme] | Inherits=YOUR_ICON_THEME_FOLDER_NAME'
5. Save the file as 'index.theme'
6. Logout and log in. Presto!