“The Events Calendar” plugin by Modern Tribe in WordPress not working

I’m using the “The Events Calendar” plugin by Modern Tribe. I have the following code at the beginning of a php file that is loaded with an ajax get statement.

if (!function_exists('tribe_create_event')) { 
    echo "function does not exist";
        return;
}

Here’s the ajax call.

jQuery.get("http://allthingsbahai.net/wp-content/themes/accelerate-child/insertdate.php",
                    {gregdate: gregdate, badidate: badidate},
                    function(result, status) {
                        alert(status);
                        alert(result);
                        //alert(result.badidate);
                        //alert(result.gregdate);
                    }            
            );

It returns with a status of success, and “function does not exist” for the result. I’m baffled at this point. The calendar works fine, accepts entries through the wordpress admin interface, and displays properly. I’m stumped