From MoodleDocs

This error occurred when adding a Glossary entry Moodle 2 I have not yet determined the cause.

Field "LOWER(concept)" does not exist in table "glossary_entries" John Fisher

John - this was a bug fixed the other day here:

This error is persisting in the Moodle Glossary on this date but not in the Moodle 2.0.1 release--Colin Fraser 14:35, 2 January 2011 (UTC)