Unable to delete static pages

Hi there…
I’m using WordPress on several sites, but i ran into a problem few hours ago on one of the sites.

I’m able to change/edit and create new pages, but im unable to delete my pages. When i press the delete button, it sometimes says “data sent”, but i also recieve this error:
https://www.anjay.dk/error.jpg

I’ve disabled all plugins, and checked chmod, even tried to give them 777… It’s not working….

I really need some support on this subject, so if you know the answer, help me out…

Thanks