Vnc viewer not working

I am running SUSE12 SP4 in a machine, i connected this machine with a laptop where open suse 11.3 is running , when i tried vncviewer ip:port (of SUSE12 Sp4) The error

is displayed.
can you help me with a solution TIA

@aman Hi, 11.3?? That is way out of date? Can you ssh onto the system in question and check if an existing vnc has not been exited properly?