[Plugin: WordPress Hit Counter] Unique Visitors are not counted

Hey everybody!
I realy love the WordPress Hit Counter, the designs and how it works. A great plugin at all!
But I have a problem:

On my new website: http://www.jkproduktion.de the counter is used at the end of the sidebar. I want to count the UNIQUE visits but it adds a number on every page view. So I checked the “Count only unique visitors? (resets every 24h)” field – but it it doesn’t changed the counting.

Please help me 🙂
Greetings from Germany!

http://ww.wp.xz.cn/extend/plugins/wordpress-hit-counter/