A menu item gives the followinf error 1064

This is the first time I see this error since Iam learning and working with joomla?
a menu item gives me this error:
Oops, you've encountered an error 1064
It appears the page you were looking for doesn't exist. Sorry about that.
Naslovnica - Contact Webmaster

the page is an K2 item that works fine when using the category layout and clicking separately on the item:
http://www.ka-mont.si/industrijska-vrata.html
but when I click on http://www.ka-mont.si/industrijska-vrata/industrijska-vrata.html which is the second submenu item I get this error???
I am supposed to this site: http://www.ka-mont.si/industrijska-vrata/item/51-industrijska-sekcijska-vrata.html
why is this happening?
Thank you

Please firstly try to remove SEF URL's. When you still get this message please try to remove all modules visible on this site.

doesnt help!
disabled SEF and the only module was menu in sidebar...

what next?

Please try to unpublish modules visible on this pages, or better create just some test menu item linked with soem article.

as I cant see any module except the logo and menu module... I have created "test menu item" linked it to your typhograhy article and same error appears?? http://www.ka-mont.si/test.html

I have searched all over even in jooma community, and they reply its a problem with gavick templates?

I dont know what is going on it suddenly started working?
why is this happening?

Could you provide me details via PM to your backend ? Did you check whether this URL's are working with the default beez template ?

I did send you my credentials, but at the moment everything works fine?
as a matter of fact I havent tested with the default template as I didnt think of that

maybe you can find a possible configuration error? I have installed the start package with the demo content...

Maybe this was related with publish date of your articles. Please make some tests and if you notice any problems let me know.