Thread:Extension talk:WikiEditor/preview and change not working on my wiki?

I have the latest stable mediawiki (1.24) and the latest stable wikieditor

When I press on "Preview" or "Changes", it does not work, I see the spinning wheel that says "Loading", but it just spins forever and nothing happens?

I disabled those tabs in localsettings for now, but how can I find out whats causing the problem?