I installed new theme named Simple-Catch. It was working properly but suddenly something happened and it looks like corrupted the theme. now if I open my website it shows 'Fatal error: Call to undefined method WP_Query::is_main_query() in /home/content/35/8607935/html/wp-content/themes/simple-catch/functions/simplecatch_functions.php on line 718'
Even I am unable to login to remove this theme. my website is 'http://www.jesserabiad.com/' and login address is 'http://www.jesserabiad.com/wp-admin'
plz tel me some way to resolve this problem. I am unable to access even my login page.