You can try editing 'Setting.php' in the root of your forum - look for this section:
########## Database Info ##########
$db_type = 'mysql';
$db_server = 'localhost';
$db_name = 'name_of_db';
$db_user = 'db_user';
$db_passwd = 'db_password';
$ssi_db_user = '';
$ssi_db_passwd = '';
$db_prefix = 'smf_';
$db_persist = 1;
$db_error_send = 0;
Change
$db_persist = 1;
to:
$db_persist = 0;