synergy and ssh problems

[Voorhees51]

I am using synergy so I can use 1 mouse, and keybord with mulitple monitors.

It is working fine when I run it without ssh for the encrypttion, but when I try to use ssh it gives me an error:

I followed the guide on their site about using ssh
when I try the:
ssh -f -N -L 24800:server-hostname:24800 server-hostname
using the hostname I specified in my conf file it ssh gives me the following error:

channel_setup_fwd_listener: cannot listen to port: 24800
Could not request local forwarding.

What could be causing this to happen and how do I go about fixing it, any help would be much appreciated

--thanks