I have a survey which is working fine except when it reaches on the last page where it will show the below error:

Warning: Attempt to assign property of non-object in /var/www/html/common_functions.php on line 4260

Fatal error: Call to a member function SetLanguage() on a non-object in /var/www/html/common_functions.php on line 4263

Line 4260 is $mail->SMTPKeepAlive=true;
Line 4263 is if (!$mail->SetLanguage($defaultlang,$rootdir.'/classes/phpmailer/language/'))

Limesurvey version is Version 1.91+ Build 11110


When I export the survey and import in my development server(Version 1.91 Build 10089) it works fine.

Anyone have any idea how is this happening?

Please help me out!