i dont know

i have this error whin i try to convert frome phpBB 2.0.19

SQL ERROR [ mysqli ]

MySQL server has gone away [2006]

SQL

SELECT username, user_id, user_posts FROM phpbb_users WHERE user_id IN (260, 306, 1392, 4224, 4464, 4960, 7582, 8860, 10104, 10216, 11170, 11706)

BACKTRACE

FILE: includes/db/mysqli.php
LINE: 143
CALL: dbal->sql_error()

FILE: install/convertors/functions_phpbb20.php
LINE: 1856
CALL: dbal_mysqli->sql_query()

FILE: install/install_convert.php(1003) : eval()'d code
LINE: 2
CALL: phpbb_check_username_collisions()

FILE: install/install_convert.php
LINE: 1003
CALL: eval()

FILE: install/install_convert.php
LINE: 203
CALL: install_convert->convert_data()

FILE: install/index.php
LINE: 402
CALL: install_convert->main()

FILE: install/index.php
LINE: 274
CALL: module->load()