Did you do the database update?
SQL FIX
CREATE TABLE phpbb_ip_tracking_config ( max INT(15) NOT NULL default '0' ); CREATE TABLE phpbb_ip_tracking ( ip varchar(15) NOT NULL default '', time int(11) NOT NULL default '0', located varchar(255) NOT NULL default '', referer varchar(255) NOT NULL, username varchar(50) NOT NULL default '' );
INSERT INTO phpbb_ip_tracking_config VALUES (25000);
I installed it and began working right away.
That database update will remove the error.
If you still get it, you didn't do it, or it didn't take.
I did mine through cPanel with no problems.