diff --git a/sites/all/modules/mail_logger/mail_logger.module b/sites/all/modules/mail_logger/mail_logger.module
index 6d4db57..ceace6d 100644
--- a/sites/all/modules/mail_logger/mail_logger.module
+++ b/sites/all/modules/mail_logger/mail_logger.module
@@ -85,7 +85,18 @@ function mail_logger_mail_alter(&$message) {
 //this line taken from mail.inc:drupal_mail()
   $message['body'] = is_array($message['body']) ? drupal_wrap_mail(implode("\n\n", $message['body'])) : drupal_wrap_mail($message['body']);
   $message['date_sent'] = time();
+  $new_mlid = '';
+  switch ($GLOBALS['db_type']) {
+    case 'mysql':
+    case 'mysqli':
+      $new_mlid = NULL;
+      break;
+    case 'pgsql':
+      $new_mlid = db_result(db_query("SELECT nextval('{mail_logger_mlid_seq}')"));
+      break;
+  }
   $args = array(
+    $new_mlid,
     $message['id'],
     $message['to'],
     $message['subject'],
@@ -99,7 +110,7 @@ function mail_logger_mail_alter(&$message) {
   db_query("INSERT INTO {mail_logger} (
   mlid , mailkey , mail_to , subject , body , mail_from , headers, date_sent, language
   ) VALUES (
-  NULL, '%s', '%s', '%s', '%s', '%s', '%s', %d, '%s' )", $args);
+  %d, '%s', '%s', '%s', '%s', '%s', '%s', %d, '%s' )", $args);
 
   // Fire 'mail_logger' 'mail_sent' action.
   module_invoke_all('mail_logger', 'mail_sent', $message, mail_logger_email_user($message['from']), mail_logger_email_user($message['to']));