wp_mail无法处理wordpress自定义插件文件

我遇到了wierd问题。我正在使用"WP电子邮件模板"插件与mandrill。我还在"主题我的登录"插件中使用一个自定义文件，该插件需要在收到$_POST后发送电子邮件。这是一个代码

$location = $_SERVER['DOCUMENT_ROOT'];
global $wpdb;
if ( ! isset( $wpdb ) ) { 
    include( $location . '/wp-config.php' );
}
global $current_user;
/************** Wp_mail Works Fine when placed here *************/
if( isset( $_POST['organisation_name'] ) ) {    
/************** Wp_mail doesnot Work when placed here *************/
    $current_user = wp_get_current_user();
}

Wp邮件放在isset（$_POST）外部时工作正常，但放在内部时不工作。我已经仔细检查了if语句是否正确执行。EDIT：这是条件之前的Print_r（$_POST）没有什么有趣的

Array
(
    [organisation_name] => iDevels
    [representative_name] => Test Ato
    [representative_contact] => 
    [course-name] => ITIL 2011
    [course-level] => Foundation (3 days)
    [start-date] => 17/02/2015
    [end-date] => 19/02/2015
    [no-candidate] => 2
    [trainer-required] => true
    [trainer-name] => 
    [exam-required] => true
    [exam-date] => 19/02/2015
    [exam-time] => 12:00
    [exam-type] => Paper
    [proctor-name] => 
    [delivery-contact] => asdasd
    [delivery-phone] => 234234
    [delivery-address] => asdasd
    [delivery-city] => asdasd
    [delivery-postcode] => asdasd
    [delivery-country] => AT
    [exam-papers] => delivery location
    [training-venue-location] => Same as delivery location
    [training-contact] => asdasd
    [training-phone] => 234234
    [training-address] => asdasd
    [training-city] => asdasd
    [training-postcode] => asdasd
    [training-country] => AT
    [_wpnonce] => cc65d65d0c
    [_wp_http_referer] => /customer-area/?settings=order-training
)