Fatal error showing up

Hello, i have recently changed my theme, but now i am getting the following error below every post title,
Warning: error_log() has been disabled for security reasons in /home/rwbunive/public_html/wp-includes/wp-db.php on line 1036

i googled it but could not find possible solution, please any help is expected
Thank you.
URL to my site is techblogmaster dot com