After adding Domain, the page refreshes and nothing happens. Checked the FAQ, that's not it.

Hey there

I tried installing Domain Mapping, which worked fine. But if I try to add a domain and click add, the page reloads and everything stays the same.

The FAQ says, the SUNRISE-constant might be defined to low in the wp-config.php, which isn't the case. Also I've tried with and without multi-domains (renamed dm_sunrise.php and sunrise.php), and it didn't work either way.

I have a clean WP 3.4.2 install without any other plugins or themes installed.

Any ideas what to try?