Error 403 when trying to add articles or change any options

Maybe someone can help debugging, when he see the menu and font-files. There is javascript-code involved, hope that this doesn’t cause the bug:

schriftart.dcstyle.json.html (437 Bytes)
piwik-statistiken.dcstyle.json.html (1.1 KB)
menue.dcstyle.json.html (6.6 KB)