Database Error!

Error: Field 'last_seen' doesn't have a default value
Query: INSERT INTO users (uid, password, ip_address, first_seen) VALUES ("5dea9a15232b12.68732881", "2HkLqhYAUKOgcHkYeeHjjsCWtA6zfDaZ", "34.225.194.144", UNIX_TIMESTAMP())
File: /includes/database.class.php
Line: 98
Backtrace: