I interviewed my parents and sister for the definitions of literature and civilizations.  These are their responses:
Dad:     Literature: Written language.  Written language by definition sends a message.  There is scientific literature that i refer to every day when discussing medical treatment. There is artistic literature such as novels and short stories.  There is informative literature such as print media.
            Civilization:  A large group of people sharing common ideals and technologies.  Most of the developed world today I think of as a part civilization but there are groups of people and cultures that live outside of our civilization but may be part of a different civilization.

Mom:     Literature:  Written works to express a thought, emotion, or lesson.
              Civilization: A community of people that have a common, developed way of life.

Sister:     Literature: works of authors including poems, songs, books, plays and other writings that give insight into a particular culture.
               Civilization:  A group of people with their own cultures and customs which develops over time

I would say literature includes any written works which possess some sort of meaning or value artistically and a civilization is a society which has reached a level of sophistication that allows it to be self-supportive and productive.