You must be more verbose. Does ubu_create.sh finished without errors? Try ubu_close.sh and then ubu_chroot.sh once again. You can also uncomment set -x from ubu_* scripts and in image /usr/share/ubu_chroot/

For gui try ubu_install.sh (qxcompositor, lxde) and read instruction about qxcompositor on openrepos.

BTW slimport support is not in master branch and is untouched since eons.