It means that we should not value education because it's a hard thing to do. Or we shouldn't force ourselves to self-educate ourselves with no dream. Filling the pail is what learning from memorizing means and as long as we are memorizing hard things while we're not understanding what it means, then education will be a stressful thing for us to do. While Lighting the fire means that we are learning and enjoying what we're doing. It means that we should not only learn books and lessons but also things that we can use to stand with our own feet. Education should light our guide to the right path :))

p.s I just interpreted it on my own way, sorry if its lame or not so good XD