Error message

• Notice: Trying to access array offset on value of type int in element_children() (line 6609 of /home/customer/www/njpls.nou.edu.ng/public_html/includes/common.inc).
• Deprecated function: implode(): Passing glue string after array is deprecated. Swap the parameters in drupal_get_feeds() (line 394 of /home/customer/www/njpls.nou.edu.ng/public_html/includes/common.inc).