Warning: Undefined property ERROR

[apt302]

i keep getting this error:
(1)
Warning: Undefined property: host in util.php on line 120

line 120 looks like this:
if (!$this->host) {

	$this->host = HOSTSERVER;



	}		

the variable is defined at the top of the page like this:

define("HOSTSERVER", "64.248.39.189" );

(2)
Warning: Undefined variable: SERVER_NAME in util.php on line 136

line 136 looks like:
MySQL_ErrorMsg("Unable to connect to MySQL server: $this->host : '$SERVER_NAME'");