คือมีปัญหาให้การ connect DB ของ ms sql ค่ะ ใครมีคำแนะนำช่วยหน่อยนะคะ

อันนี้โค้ด connect ค่ะ
$active_group = 'mssql';
$active_record = TRUE;

$db['mssql']['hostname'] = "xxx.xxx.xxx.xxx";
$db['mssql']['username'] = 'sa';
$db['mssql']['password'] = 'xxx';
$db['mssql']['database'] = 'xxx';
$db['mssql']['dbdriver'] = 'mssql';
$db['mssql']['dbprefix'] = '';
$db['mssql']['pconnect'] = FLASE;
$db['mssql']['db_debug'] = TRUE;
$db['mssql']['cache_on'] = FALSE;
$db['mssql']['cachedir'] = '';
$db['mssql']['char_set'] = 'utf8';
$db['mssql']['dbcollat'] = 'utf8_general_ci';
$db['mssql']['swap_pre'] = '';
$db['mssql']['autoinit'] = TRUE;
$db['mssql']['stricton'] = FALSE;

พอรันแล้วขึ้น blank page ค่ะ
ปล. Uncomment ในไฟล์ php.ini ที่ extension=php_mssql.dll ออกแล้วค่ะ