I've recently received my iMac back after repairs at the Apple Store. There was a hard drive failure, so they put a new HDD in. I restored from a Time Machine backup, and everything is working fine (apart from the mammoth amount of podcasts and such I've got to catch up with). The only thing I'm having problems with is iChat. I use it connect to Facebook IM through the Jabber protocol, but I'm finding I can't send or receive messages. There's no error message or anything like that; if I type a message into the box and press Enter, the focus jumps away from the chat window. I've tried deleting and setting up my account in iChat, deleting all the preferences and starting from scratch twice, and it's still not working. The same problem occurs: whenever I try to send a message (by pressing Enter), the focus jumps from the chat window.