I am unable to award a bounty to my question on SO.
I tried it on two different systems (one has a direct connection and one connects through a proxy) and with a wide spectrum of different browsers (firefox, konqueror, explorer 8 and chrome).
In all cases, the confirm question ("this can't be undone") appeared perfectly, but after that nothing happened.
The most informative error message I've got is coming from a firebug:
Explorer 8 gives the following error message:
What to do now?