PHPBB 3.0.8 Admin Error

[mark.magill83]

When attempting to enter the admin section of my PHPBB 3.0.8 forum I receive the following error 80% of the time, has anyone any ideas as to the cause:

General Error
SQL ERROR [ mysqli ]

Lost connection to MySQL server during query [2013]

SQL

SELECT COUNT(attach_id) AS total_orphan FROM phpbb_attachments WHERE is_orphan = 1 AND filetime < 1293050515

BACKTRACE

FILE: includes/db/mysqli.php
LINE: 163
CALL: dbal->sql_error()

FILE: includes/acp/acp_main.php
LINE: 490
CALL: dbal_mysqli->sql_query()

FILE: includes/functions_module.php
LINE: 507
CALL: acp_main->main()

FILE: adm/index.php
LINE: 74
CALL: p_master->load_active()