Since the default configuration uses matchbox and openbox, the themes should be in /usr/share/themes
To change the theme, as far as I know, you have to do it manually by editing rc.xml. That file can be found in /etc/xdg/openbox. Copy everything inside this directory to /home/root/.config/openbox (note that /home/root is your home directory).
Open rc.xml, find the <theme> <name> tag and change the theme name into the one that you want (again, you can find the theme in /usr/share/themes). However, I'm using r121 and not really sure if this works for the other version as well. Good luck