iWires HDMI Cable - MBP to Sanyo TV

Hi ,

After much trawling for a solution to my dilemma i have decided to
"put my question out there" in the hope that the Apple online community
can assist.

Here goes , please forgive my terminology errors , i am a Mac convert of only 5 months !
I have a MBP 13" , OSX 10.6.6 , purchased last October , from the Apple store MK England.

I wish to watch films that are stored on my MBP on my Sanyo HD television.

I have purchased, again through Apple a 2mtr Mini Display Port to HDMI Cable ( iWires )

I have inserted the HDMI end into HDMI Port 1 on the back of my TV
I have inserted the Mini Port end into the slot on the side of my MBP.

Select HDMI - 1 as the source on my TV , turn off Sky Box box , and start the film ,
thats it , all i see on my TV is a mac background , no visual , and no sound

Do i need to "do" anything to my MBP to make this work ?

Any assistance would be greatly appreciated ,

Thanks in advance ,

Russ