I get some error warning after installation of my wordpress theme cryption.

When i search for a page or make any updates to a certain page post etc i see this error. 

Warning: Missing argument 2 for CT_Mega_Menu::replace_walker_class() in /home3/snwokenk/public_html/wp-content/themes/cryption/inc/megamenu/megamenu.class.php on line 181

Warning: Cannot modify header information - headers already sent by (output started at /home3/snwokenk/public_html/wp-content/themes/cryption/inc/megamenu/megamenu.class.php:181) in /home3/snwokenk/public_html/wp-includes/pluggable.php on line 1216

Also on my dash board i get another warning  

Warning: Missing argument 2 for CT_Mega_Menu::replace_walker_class() in /home3/snwokenk/public_html/wp-content/themes/cryption/inc/megamenu/megamenu.class.php on line 181

Warning: Cannot modify header information - headers already sent by (output started at /home3/snwokenk/public_html/wp-content/themes/cryption/inc/megamenu/megamenu.class.php:181) in /home3/snwokenk/public_html/wp-includes/option.php on line 919

Warning: Cannot modify header information - headers already sent by (output started at /home3/snwokenk/public_html/wp-content/themes/cryption/inc/megamenu/megamenu.class.php:181) in /home3/snwokenk/public_html/wp-includes/option.php on line 920

Please how do i fix this issue cause i need to get my site up and running by thursday. thanks