iChat Connection Failure when Sharing Desktop Screen

I had repeated failures when I was trying to control someone elses screen using iChat. The message was something similar to 'No Data has been received in the last 10 seconds' and the screen sharing would end after briefly showing the other person's desktop.

I got it working and I think it was one of three things:

1. WiFi not providing enough bandwidth. (Doubtful, as it also did it using a wired network.)
2. The Remote Desktop 3.2.2 (IIRC that is the version number, it showed up on 13 Jan 2009 software update check.)
3. Under Video and Audio Settings in iChat, I had my bandwidth limited to 500Kbps.
4. Having invalid audio and video devices set (like a bluetooth headset not paired or connected).

My Money is on #3, but I included the other changes I made during troubleshooting.

My preferences for iChat:

This was on OS X, chatting between 10.5 and 10.6 OS versions over the internet via an AIM buddy list contact.

We encountered this problem (loss of audio in iChat):

http://forums.macrumors.com/archive/index.php/t-186194.html

And it was solved in the manner in that post, namely, killing coreaudiod and restarting iChat.

He could hear me, but I couldn't hear him, when a short time before it was working fine.