Tournament error

I can’t edit the fields when making a tournament. In Firefox nothing happens when clicking the individual options, in Safari I manage to get to the actual fields to edit stuff but when trying to save I only get a generic Error message (see attachment).

Additionally, when trying to select a game there seems to be a UI bug.

Any idea what the cause of this is? The server log shows no errors, only a GET and POST as expected. All caching is disabled to ensure that this isn’t a caching/ajax issue.