Breakable MVC framework written in PHP

I've written a framework in MVC, I call it Midget MVC, as it's so darn small. The reason I wrote it is because I wanted a lightweight and extendible framework to use in projects. It eventually got abandoned due to it's break-ability and my lack of experience in the subject. However, I've got a bigger project I'm working on and need a framework, so I want to start re-writing MMVC. Feel free to view the entire project here.

The main piece of code I want looked over is the router class. After talking a bit on the PHP IRC I discovered that it was indeed breakable. One of the recommendations made was for me not to use global $config. What's the best way to do this?

<?php

class Route {
    public function load(){
        global $config;
        if(isset($_SERVER['PATH_INFO'])){
            $route = explode('/', substr($_SERVER['PATH_INFO'], 1));
            $controller = ucfirst(strtolower($route[0]));
            $method = isset($route[1]) ? strtolower($route[1]) : 'index';

            $path = APPPATH . "controllers/" . $route[0] . ".php";
            if(realpath($path)){
                require $path;
                $controller = new $controller;

                if($method != 'index'){
                    $variables = array();
                    $i = 0;
                    foreach($route as $vars){
                        if ($i >= 2)
                            $variables[] = $route[$i];
                        $i++;
                    }

                    call_user_func_array(array($controller, $method), $variables);
                }else{
                    $controller->index();
                }
            }
        }else{
            $controller = $config['deafult_controller'];
            require APPPATH . "controllers/" . $controller . ".php";
            $controller = ucfirst($controller);
            $controller = new $controller;
            $method = 'index';
            $controller->$method();
        }
    }
}

The second thing I want help with is the load class. Is there a better way to load models into the controller? Loading library files was quite difficult; you have to load it in each file. If you load the library in the controller, you'll have to load it again in the model if you want to access it. What's teh best way to do this?

class Load{
    function __construct($controller){
        $this->controller = $controller;
    }

    // loads a specified model
    public function model($model){
        $model = strtolower($model);
        if(file_exists(APPPATH . "models/$model.php")){
            require(APPPATH . "models/$model.php");
            $modelclass = ucfirst($model . '_Model');
            // call function to include it in the controller
            $this->controller->$model = new $modelclass;
        }
    }

    // loads a veiw
    public function view($view, $data = NULL){
        // asign filepath
        $path = APPPATH . "views/" . $view . ".php";
        // asign variables if $data is set
        if($data != NULL)
            foreach($data as $var => $value)
                $$var = $value;

        if(file_exists($path)){
            ob_start();
            require($path);
            print(ob_get_clean());
        }else
            return false;
    }

    public function library($library){
        $library = strtolower($library);
        if(file_exists(LIBRARY . "$library.php")){
            require(LIBRARY . "$library.php");
            $libraryclass = ucfirst($library);

            $this->controller->$library = new $libraryclass;
        }
    }
}

And finally, how secure is the entire thing. What security flaws can you see? Are there any major points I should improve upon. I apologise if this post isn't quite up to scratch; it's my first time posting here.

Thank you very much! I look forward to reading any responses.