I have recently upgraded to 5.0.4, i have the below errors ast top of admin area:

Notice: Undefined property: User::$group_ID in ../public_html/inc/_core/model/dataobjects/_dataobject.class.php on line 574

Warning: Cannot modify header information - headers already sent by (output started at ../public_html/inc/_core/model/dataobjects/_dataobject.class.php:574) in ../public_html/inc/_core/_template.funcs.php on line 59

Warning: Cannot modify header information - headers already sent by (output started at ../public_html/inc/_core/model/dataobjects/_dataobject.class.php:574) in ../public_html/inc/_core/_template.funcs.php on line 267

Warning: Cannot modify header information - headers already sent by (output started at ../public_html/inc/_core/model/dataobjects/_dataobject.class.php:574) in ../public_html/inc/_core/_template.funcs.php on line 268

Warning: Cannot modify header information - headers already sent by (output started at ../public_html/inc/_core/model/dataobjects/_dataobject.class.php:574) in ../public_html/inc/_core/_template.funcs.php on line 269

Warning: Cannot modify header information - headers already sent by (output started at ../public_html/inc/_core/model/dataobjects/_dataobject.class.php:574) in ../public_html/inc/_core/_template.funcs.php on line 270

I have inspected lines 566 - 575 but they did make no sense to me (_dataobject.class.php)

	/**
	 * Get a member param by its name
	 *
	 * @param mixed Name of parameter
	 * @return mixed Value of parameter
	 */
	function get( $parname )
	{
		return $this->$parname;
	}