user warning and hub.py problem

[jacksledger]

can you help us?
I was learning about RYU controller and was trying to run this multipath program and i am getting this following errors.
/home/ubuntu/ryu/ryu/topology/switches.py:478: UserWarning: Datapath#ports is kept for compatibility with the previous openflow versions (< 1.3). This not be updated by EventOFPPortStatus message. If you want to be updated, you can use 'ryu.controller.dpset' or 'ryu.topology.switches'.
for port in dp.ports.values():
Available paths from 6 to 1 : []
Path installation finished in 0.000164031982422
hub: uncaught exception: Traceback (most recent call last):
File "/home/ubuntu/ryu/ryu/lib/hub.py", line 52, in _launch
func(*args, **kwargs)
File "/home/ubuntu/ryu/ryu/base/app_manager.py", line 275, in _event_loop
handler(ev)
File "/home/ubuntu/ryu/ryu/app/ryu_multipath.py", line 289, in _packet_in_handler
out_port = self.install_paths(h1[0], h1[1], h2[0], h2[1], src_ip, dst_ip)
File "/home/ubuntu/ryu/ryu/app/ryu_multipath.py", line 214, in install_paths
return paths_with_ports[0][src][1]
IndexError: list index out of range

I was running the code using own topology created a follows
from mininet.topo import Topo

class MyTopo(Topo):

    def __init__(self):

            Topo.__init__(self)

#add hosts and switches
h1 = self.addHost( 'H1' )
h2 = self.addHost( 'H2' )
s1 = self.addSwitch( 'S1' )
s2 = self.addSwitch( 'S2' )
s3 = self.addSwitch( 'S3' )
s4 = self.addSwitch( 'S4' )
s5 = self.addSwitch( 'S5' )
s6 = self.addSwitch( 'S6' )

#add links
self.addLink( h1, s1 )
self.addLink( h2, s6 )
self.addLink( s1, s2 )
self.addLink( s2, s3 )
self.addLink( s3, s6 )
self.addLink( s1, s4 )
self.addLink( s4, s5 )
self.addLink( s5, s6 )

topos = { 'mytopo': (lambda:MyTopo() ) }

please provide us some solution to overcome these errors