How to install ksu on self-hosted KalturaCE server?

KalturaCE is installed and is working.
I have downloaded "KSU Integration script." and changed constants like this:

define("KALTURA_PARTNER_ID", 1);
define("KALTURA_PARTNER_WEB_SERVICE_SECRET", '6ebfcf496f8eef7...');

Now... I get:
Fatal error: Uncaught exception 'KalturaException' with message 'Error while starting session for partner [1]' in /var/www/test/web/kaltura_client_v3/KalturaClientBase.php:307 Stack trace: #0 /var/www/test/web/kaltura_client_v3/KalturaClient.php(3683): KalturaClientBase->throwExceptionIfError(Array) #1 /var/www/test/web/ksu.php(18): KalturaSessionService->start('6ebfcf496f8eef7...', 'ANONYMOUS', 0) #2 {main} thrown in /var/www/test/web/kaltura_client_v3/KalturaClientBase.php on line 307

What is that.. i have no idea. From this exceptions I cannot understand where is the problem.

In ksu.php there is http://www.kaltura.com/kupload/ui_conf_id/11500, I suppose I must change that to url on my server, but... to what?

(btw my first impression is that kaltura is great, but the documentation is awful. I am lost in kaltura's site, does not understand where to start from. And with ksu I am not sure is the integration script supposed to work on self-hosted platform or not. I am even not sure is Kaltura Client Library - PHP is supposed to work with self-hosted solution or not. No demos/docs for php client library usage.)