Use the Community-Maintained Ubiquity instead of the Mozilla Labs: Ubiquity, then Ubiquity in Awesomebar will work. Go to https://bitbucket.org/satyr/ubiquity/downloads/tip.xpi for the Community-Maintained Ubiquity, then go to https://addons.mozilla.org/en-US/firefox/addon/ubiquity-in-awesomebar/ for Ubiquity in Awesomebar.