I am running a towny server. Towny uses "town-<townname>" to store the amount of money a particular town has using iConomy (through Register.jar?). Anyways, I saw that a user had made a town with a long name, and this was causing this error:

2011-12-30 09:59:48 [INFO] [iConomy] Error issueing SQL query: java.sql.SQLException: Data truncation: Data too long for column 'username' at row 1 Query: INSERT INTO iConomy(username, balance, status) values (?, ?, ?) Parameters: [town-the_brotherhood_of_the_red_crucifix, 30.0, 0]

I upped the length of the username column to 128, and we've been good since then.