Upload these:
admin/
cache_builders/ (not the cache_builders/custom/ subdirectory)
images/
install/
languages/
libs/
scripts/
styles/admin.css
styles/common.css
styles/images/
templates/default/
ubb_js/
credits.html
index.php
ubbthreads.php
Do not upload these:
cache_builders/custom/
includes/
styles/wrappers.php