I'm not sure what you're forwarding with 57999 and 5903. To do X forwarding, all you need to enable is the 'x forwarding' option. If the DISPLAY variable is not set, then the X forwarding option is probably disabled on your server. Check the sshd_config (probably in /etc/ssh)
You'll still need to be running some kind of X software on the client side. I use xwin32 myself (
www.xwin32.com)
Let me know if you need more info
Brian