Please check out this MTL forum posting, it provides a step-by-step guide. Basically you should have the same port number in your tunneling parametersas your VNC server displaynumber.
http://software.intel.com/en-us/forums/showthread.php?t=76570&o=a&s=lr
Alternatively you could try Xming - it's much easier to set up.
Having trouble getting VNC to work
I am trying to remote into the login node using VNC (specifically Real VNC and Ultra VNC). I am using Putty for ssh tunneling. With Real VNC I get "read: connection reset by peer (10054)" after entering my password. With Ulra VNC I get "Write extract: Socket error while writing" I am using "L5901 localhost:5900" as my tunneling parameters for putty. My understanding is that this means that if I VNC into localhost:5901 I will get forwarded to 5900 on the login node. Are there any detailed instructions available for this. Thanks.