Chat doesn't seem to be working at all

Ho,

have tried to use the chat activity (for backup purposes) and here it's impossible to get it working (no matter of the type of chat I select):

• "Ajax chat room": Shows one "loading" div that never ends
• "(Use more accessible interface)": Shows one "horrible" (orange) div. Entering one message and submitting it leads to "There are no Chats in this course" error.
• "Click here to enter the chat now": Simply causes 100% blank page to be shown

This makes chat completely unusable...

Ciao

PS: Only tested with Safari