Database Error!

Error: Field 'last_seen' doesn't have a default value
Query: INSERT INTO users (uid, password, ip_address, first_seen) VALUES ("5c96e422bc7492.65830534", "GHL3zfK9zSa0sTn5Jbf6ePVQ14OADvid", "107.23.176.162", UNIX_TIMESTAMP())
File: /includes/database.class.php
Line: 98
Backtrace: