quick time won't play i tunes

I am a brand new iTunes user. I just downloaded a Dr Who television episode S7E1. I tried to play it (I am PC) and the message popped up saying I need to have Quick Time installed to play movie. I installed it and it still wouldn't play. I uninstalled it and installed again and everytime I click on play I get the same error message. I have quick time newely downloaded. I have it opened and iTunes opened. I click the play button on my program i wish to view and i get the same error message.

I looked in quick time and can see nothing related to itunes to see if i could go through that program to get to my show.

What am i doing wrong - or not doing - or don't know? I just want to watch Dr. Who like an hour ago.

Please help.