Error message

• Notice: Undefined variable: prev_chapter in _nav_srimad_content() (line 1757 of /var/www/gitasites/sites/all/modules/gitasites/gitasites.module).
• Notice: Undefined variable: next_chapter in _nav_srimad_content() (line 1760 of /var/www/gitasites/sites/all/modules/gitasites/gitasites.module).
• An illegal choice has been detected. Please contact the site administrator.