Illegal string offset 'flickr-sequence' in 错误

        $fopts = get_option($this->fopt);
        $fopts['flickr-sequence'] = $sibling_node;
        if (strpos($sibling_node, '>') === 0)
        {
            $ret = substr($sibling_node, $this->pos, $this->size - $this->pos);
            $this->char = null;
            $this->pos = $this->size;
        }
        update_option($this->fopt, $fopts);

Warning: Illegal string offset 'flickr-sequence' in 这个错误如何修正？

Warning:Illegal string offset'flickr-sequence'..错误