Illegal String Offset

Uh, I need some help. I’m getting a weird error on my wife’s website. Check out http://lactationwise.com/benefits.

The error is:

Warning: Illegal string offset ‘title’ in /home/scottyhuff/public_html/lactationwise.com/wp-content/themes/nictitate-pro-1.0.11/library/includes/shortcodes.php on line 239

the code it’s pointing to is this (the line in question include $atts[‘title’]):

function kopa_shortcode_accordion($atts, $content = null) {
   extract(shortcode_atts(array(
        'title' => 'Accordion Title'
                    ), $atts));
    return '<div class="accordion-title">
                <h3><a href="#">' . $atts['title'] . '</a></h3>
                    <span>+</span>
            </div>
            <div class="accordion-container" style="display:none;">' . do_shortcode($content) . '</div>';
}

I upgraded her theme a week ago, but I didn’t notice this until today. What do I do about it?