Unable to post or edit

When I want to edit or add pages, nothing happens when I push the “edit” button inside the publishing block on the right. Neither does any of the preview options work.

Until yesterday everything worked properly, but since last night something went wrong. Is this a Java-problem?

I use the twentyeleven theme and today I deleted all plugins, because of the edit-issues. The only two left are the akismet and the si-contact-form.

I looked at the changes I made the last 24 hrs, but I did not touch the WP-files themselves at all.

Thank you all in advance!