$ mail - ＆gt; send（）无效

Question

我有PHP代码发送邮件取决于消息和正文。但是邮件没有被发送而且没有错误

谁能告诉我这里的问题是什么

if ($userid == null) {
  $smtpusername     = "smtp". rand(1,20)."@nithin.com";
  $mail->IsSMTP();                   // telling the class to use SMTP
  $mail->SMTPAuth   = SMTPAUTH;      // enable SMTP authentication
  $mail->Host       = SMTPHOST;      // sets the SMTP server
  $mail->Port       = SMTPPORT ;     // set the SMTP port for the GMAIL server
  $mail->SMTPSecure = SMTPSECURE;    // Use ssl or tls to secure smtp calls
  $mail->Username   = $smtpusername; // SMTP account username
  $mail->Password   = SMTPPASSWORD;  // SMTP account password
  $mail->SetFrom('nithin@nithin.com','abc');
  $mail->SMTPDebug = 1;
}
else {
  //TODO: Fetch preferences, refer Taskera 1.0 version
}
$toarray          = explode(',', $to);
$mail->Subject    = $subject;
$mail->MsgHTML($htmlbody);
for($toiter = 0; $toiter < count($toarray); $toiter++)
  $mail->AddAddress($toarray[$toiter], "");
$result = ($mail->Send());
if (!$result) {
   $this->debug('MAILERROR', __FUNCTION__, 'Message sending failed. Error: ' . $mail->ErrorInfo);
  return FAILURE;
}

错误

[Tue Jul 07 09:55:24 2015] [error] [client 192.168.1.232] PHP Catchable fatal error:  Object of class PHPMailer could not be converted to string in /var/www/inc/base.inc on line 68, referer: https://www.nithin.com/

第68行

protected
  function debug($function, $variable) {
    if (is_array($variable))
      $output = sprintf(" DEBUG: == %s()     [%s]", $function, print_r($variable, true));
    else
      $output = sprintf(" DEBUG: == %s()     (%s)", $function, $variable);
    error_log($output);
  }