"Your DBMS seems to be PostgreSQL 9.3 or earlier which doesn't support Empty SELECT lists (support was added since v. 9.4).
As far as phpBB states support of PostgreSQL 8.3+ that's a phpBB bug in the function sql_table_exists() in Postgres database tools.
SELECT FROM information_schema.tables there should be probably SELECT * FROM information_schema.tables to be PostgreSQL 8.3+ compatible."

 
See: https://www.phpbb.com/community/viewtopic.php?t=2643088&e=1&view=unread#unread