My new Macbook air won't connect to my Vizio HDTV.

My new Macbook Air won't connect to my Vizio VO32LF HDTV. I bought a mini-displayport to HDMI cable to connect the two. When I connect the cable, and switch to the appropriate HDMI input on the TV, my Macbook Air screen will flash blue for a second, and then return to normal. The TV reports it's unable to find a signal. I use the HDTV as my primary monitor, so I'd really appreciate some help on getting the two to place nicely together!