Membership plugin, blank screen

Hi, I just bought membership premium plugin, I already had the free version installed. I deactivated the free version and activated the premium plugin, this resulted in a blank screen. Site was down.

I renamed the plugin directory, in order to deactivate the plugin, and activated the old (free) one. I turned on debugging in wp-config, and saw the following lines (see below) I never noticed them because I never udes the debugging with this plugin

WP version: 3.7.1
PHP Version 5.3.3-7+squeeze18

Deprecated: Assigning the return value of new by reference is deprecated in /var/www/clients/client1/web22/web/wp-content/plugins/membership/membershipincludes/classes/class.ping.php on line 307 Deprecated: Assigning the return value of new by reference is deprecated in /var/www/clients/client1/web22/web/wp-content/plugins/membership/membershipincludes/classes/class.ping.php on line 323 Deprecated: Assigning the return value of new by reference is deprecated in /var/www/clients/client1/web22/web/wp-content/plugins/membership/membershipincludes/classes/class.ping.php on line 445 Deprecated: Assigning the return value of new by reference is deprecated in /var/www/clients/client1/web22/web/wp-content/plugins/membership/membershipincludes/classes/class.ping.php on line 449 Deprecated: Assigning the return value of new by reference is deprecated in /var/www/clients/client1/web22/web/wp-content/plugins/membership/membershipincludes/classes/class.ping.php on line 461 Deprecated: Assigning the return value of new by reference is deprecated in /var/www/clients/client1/web22/web/wp-content/plugins/membership/membershipincludes/classes/class.ping.php on line 465 Deprecated: Assigning the return value of new by reference is deprecated in /var/www/clients/client1/web22/web/wp-content/plugins/membership/membershipincludes/classes/class.ping.php on line 483 Deprecated: Assigning the return value of new by reference is deprecated in /var/www/clients/client1/web22/web/wp-content/plugins/membership/membershipincludes/classes/class.ping.php on line 487 Deprecated: Assigning the return value of new by reference is deprecated in /var/www/clients/client1/web22/web/wp-content/plugins/membership/membershipincludes/classes/class.ping.php on line 492 Deprecated: Assigning the return value of new by reference is deprecated in /var/www/clients/client1/web22/web/wp-content/plugins/membership/membershipincludes/classes/class.ping.php on line 496 Deprecated: Assigning the return value of new by reference is deprecated in /var/www/clients/client1/web22/web/wp-content/plugins/membership/membershipincludes/classes/class.ping.php on line 510 Deprecated: Assigning the return value of new by reference is deprecated in /var/www/clients/client1/web22/web/wp-content/plugins/membership/membershipincludes/classes/class.ping.php on line 514 Deprecated: Assigning the return value of new by reference is deprecated in /var/www/clients/client1/web22/web/wp-content/plugins/membership/membershipincludes/addons/integrated.wproles.php on line 14 Deprecated: Assigning the return value of new by reference is deprecated in /var/www/clients/client1/web22/web/wp-content/plugins/membership/membershipincludes/addons/integrated.wproles.php on line 52 Deprecated: Assigning the return value of new by reference is deprecated in /var/www/clients/client1/web22/web/wp-content/plugins/membership/membershipincludes/addons/integrated.wproles.php on line 93 Deprecated: Assigning the return value of new by reference is deprecated in /var/www/clients/client1/web22/web/wp-content/plugins/membership/membershipincludes/addons/integrated.wproles.php on line 94 Deprecated: Assigning the return value of new by reference is deprecated in /var/www/clients/client1/web22/web/wp-content/plugins/membership/membershipincludes/addons/integrated.wproles.php on line 110 Deprecated: Assigning the return value of new by reference is deprecated in /var/www/clients/client1/web22/web/wp-content/plugins/membership/membershipincludes/addons/integrated.wproles.php on line 111 Deprecated: Assigning the return value of new by reference is deprecated in /var/www/clients/client1/web22/web/wp-content/plugins/membership/membershipincludes/addons/integrated.wproles.php on line 139 Deprecated: Assigning the return value of new by reference is deprecated in /var/www/clients/client1/web22/web/wp-content/plugins/membership/membershipincludes/addons/integrated.wproles.php on line 140 Deprecated: Assigning the return value of new by reference is deprecated in /var/www/clients/client1/web22/web/wp-content/plugins/membership/membershipincludes/addons/integrated.wproles.php on line 156 Notice: Undefined index: subscriptions_page in /var/www/clients/client1/web22/web/wp-content/plugins/membership/membershipincludes/classes/membershippublic.php on line 2142 Notice: Undefined index: registrationcompleted_page in /var/www/clients/client1/web22/web/wp-content/plugins/membership/membershipincludes/classes/membershippublic.php on line 2241 Warning: Cannot modify header information - headers already sent by (output started at /var/www/clients/client1/web22/web/wp-content/plugins/membership/membershipincludes/addons/integrated.wproles.php:156) in /var/www/clients/client1/web22/web/wp-includes/pluggable.php on line 899