Plugin error when installing CartPress

I am getting the following error when I try to install the CartPress plugin:
Plugin could not be activated because it triggered a fatal error.

Parse error: syntax error, unexpected T_STRING, expecting T_OLD_FUNCTION or T_FUNCTION or T_VAR or ‘}’ in /hermes/bosoraweb094/b2206/ipw.taylorpt/public_html2/onecheck/wp-content/plugins/thecartpress/TheCartPress.class.php on line 52

Here is line 50-56 of TheCartPress.class.php:

class TheCartPress {

public static $tcp_shoppingCart = false;
public $settings = array();

private $saleable_post_types = array();
private $globals = array();