can't edit stories

we are running an in some parts quite collaborative blog. since the new version of antville has been set up, it's not possible anymore to edit someone other's stories (even if you are an owner).

it's possible to click "edit" and you will see the interface to edit the stories, but your changes won't be saved. this problem appears no matter what user group you choose below "This story is editable by".

additionally the contribution interface looks the old way, not like the below one in this blog. (no tags, no featured; just the old way, but ineditable now).

please, could anyone give me a hint how to solve this problem? thanks!