Error message

• Notice: Undefined index: node in mardi_preprocess_page() (line 33 of /home/mardi/public_html/sites/all/themes/mardi/template.php).
• Notice: Trying to get property of non-object in mardi_preprocess_page() (line 33 of /home/mardi/public_html/sites/all/themes/mardi/template.php).