What's wrong?

 
<?php
//requiring some files
class Picture {
//Declaration of private variables
        private $_id;
	private $_nombre;
	private $_descripcion;
	private $_descripcioncorta;
	private $_imagen;
	private $_precio;
	private $_changed = false;
//from here, it searches a 'free' id in the entries' folder. if there is a 4.php and the next file is 6.php it creates 5.php and puts there the entry (this project is over files, not over db) and if readdir() completes all the dir it creates a new id. I also jumped the _get and _set.
	public function _destruct () {
		if ($this->_changed) {
			$this->save($this);
		}
	}
//Here is the error
	public function save () {
		$file = fopen ($cuadrospath.$this->_id.".php", "w"); //it opens a stream
		if (!is_null($this->_imagen)) { //if there is an image object
			<b>$img = "$cuadro[\"" . $this->_id . "\"][\"imagen\"] = new Imagen (\"" . $this->_imagen->_url . "\");\n"; //is now when php detects an error (??) here it creates a string for writing it in a file</b>
		}else{
			$img = ""; //else it doesn't say anything
		}
		$flcont = "<?php //it builds all the pieces. i removed the first error (removing that part) but it says me the same error here
require_once ($incpath.\"class.Imagen.php\");
$cuadro[\"" . $this->_id . "\"][\"nombre\"] = " . $this->_nombre . ";
$cuadro[\"" . $this->_id . "\"][\"descripcion\"] = " . $this->_descripcion . ";
$cuadro[\"" . $this->_id . "\"][\"descripcioncorta\"] = " . $this->_descripcioncorta . ";
" . $img . "$cuadro[\"" . $this->_id . "\"][\"precio\"] = " . $this->_precio . ";
?>";
		fwrite ($file, $flcont);//writes
	}
}
?> //and exit