Error on archive page

I am new at wordpres and Iam getting the following error: the link is, your help would be appreciated

https://www.marlborocountysc.org/2013/02

Notice: Undefined variable: custom_query in /home/marlboro/public_html/wp-content/themes/toolbox/archive.php on line 102

Notice: Trying to get property of non-object in /home/marlboro/public_html/wp-content/themes/toolbox/archive.php on line 102

ypur