1062 - Duplicate entry '' for key 'PRIMARY'

insert into whos_online (customer_id, full_name, ip_address, time_last_click, last_page_url, time_entry, session_id, http_referer) values ('', '[SuMa - crawl]', '54.204.103.179', '1398290664', '/shop/Patchworkstoffe/Kinderstoffe-Motivstoffe:::2_31.html', '1398290664', '', '---')

[XT SQL Error]