View unanswered posts and you get the following general error:

General Error
SQL ERROR [ mysqli ]

Unknown column 't.topic_replies' in 'where clause' [1054]

SQL

SELECT DISTINCT t.topic_last_post_time, p.topic_id FROM phpbb_posts p, phpbb_topics t WHERE t.topic_replies = 0 AND t.topic_moved_id = 0 AND p.topic_id = t.topic_id AND (t.topic_visibility = 1 OR t.forum_id IN (1, 2)) ORDER BY t.topic_last_post_time DESC LIMIT 1001

BACKTRACE

FILE: (not given by php)
LINE: (not given by php)
CALL: msg_handler()

FILE: [ROOT]/phpbb/db/driver/driver.php
LINE: 809
CALL: trigger_error()

FILE: [ROOT]/phpbb/db/driver/mysqli.php
LINE: 187
CALL: phpbb_db_driver->sql_error()

FILE: [ROOT]/phpbb/db/driver/mysql_base.php
LINE: 48
CALL: phpbb_db_driver_mysqli->sql_query()

FILE: [ROOT]/phpbb/db/driver/driver.php
LINE: 169
CALL: phpbb_db_driver_mysql_base->_sql_query_limit()

FILE: /phpbb3/phpbb/search.php
LINE: 475
CALL: phpbb_db_driver->sql_query_limit()