I followed these instructions:phpBB : Critical Error
Error doing DB query userdata row fetch
DEBUG MODE
SQL Error : 1146 Table 'aladygma_08forum.phpbb_users' doesn't exist
SELECT * FROM phpbb_users WHERE user_id = -1
Line : 136
File : sessions.php
http://www.phpbb.com/kb/article/moving- ... hpmyadmin/
And the forum is PHPBB 2