After installing the module and running cron I received the message:

user warning: Unknown column 'node.nid' in 'field list' query: SELECT node.nid FROM ss_uc_products INNER JOIN ss_node ON uc_products.nid = node.nid WHERE node.status = 1 in /data-web7/webs/xn--ijacie-stroje-9tc.eu/sites/all/modules/uc_website_xml/uc_website_xml.module on line 394.

and rss was empty. Can you help me?