Plugin help

I am developing a map on the server, and to make the facilities in every team equal, I tried to make a plugin that does things like this:

Code:

 on tile.update at (x,y,z), sync (x,y,256-z), (256-x,y,z) and (256-x,y,256-z) 

However this doesn't work:

PHP:

public function tileUpdate(&$data){
        $player=$this->api->player->get($data->data["creator"]);
        $level=$player->entity->level;
        $x=$data->data["x"];
        $y=$data->data["y"];
        $z=$data->data["z"];
        $posO=new Position($x,$y,$z,$level);
        $posDeltaX=new Position((256-$x),$y,$z,$level);
        $posDeltaZ=new Position($x,$y,(256-$z),$level);
        $posDeltaXZ=new Position((256-$x),$y,(256-$z),$level);;
        $items=$data->class;
        $level->setBlock($posDeltaX,$level->getBlock($posO));
        $level->setBlock($posDeltaZ,$level->getBlock($posO));
        $level->setBlock($posDeltaXZ,$level->getBlock($posO));
    }

P.S. Where should I look at the src code about $this->api->addHandler() and $this->api->event()?

Another question:
I know there is a function $this->api->plugin->load($scriptName), but is there a way to unload a script?

Take a look at my NetherQuick plugin, it does something like that

What about my first question