I have Debian Sarge installed in Parallels on my MacBook Pro.
X11Forwarding hadn’t been working even though I enabled it in /etc/ssh/sshd_config. I had been working around this for while, but today it was too much. I needed to get this fixed.
Verbose output of ssh No xauth program; cannot forward with spoofing and Google lead me to a solution.
apt-get install xbase-clients
Now ssh -Y <address> ethereal tunnels X through ssh.