Unable to use 5.1 surround sound in Sony Bravia

Hi everyone,
I am having 46" Sony BRAVIA V-Series LCD HDTV (model: KDL-46V4100) and I am trying to setup my Roku with surround sound and selecting 5.1 audio in Netflix. But, I am getting error on the TV that the audio signal is not supported. I have connected these using HDMI cables.
Does anybody else have the same issue? How can I use surround sound 5.1 on Netflix in my TV? Please suggest me a solution. Thanks in advance for your help.
