Q: Receive download error (-50) when downloading movie on iTunes ?

Hey. I hope someone can help me because trying to contact Apple support is a long endevour...... I am trying to download a movie (which previous three downloaded, perfectly) When I bought the movie last night it started to download immediately, great, not 3 mins later I receive the message that an error ocurred and was having difficulty connecting to internet. I've restarted my computer, restarted my internet, switched my WiFi connect (on comp) off and restarted it. And still the error occurs.... Its telling me that there is not connection to the internet, but I HAVE FULL connection in all ends. The internet works, through FireFox for my as I type, and I believe the problem lies within iTunes. This concerns me becuase not 20 mins before I purchased the movie I downloaded a previous TV Show which I have a season pass for. Does anyone know why this is happening ? Any support / suggestions is APPRECIATED ! Thank you for reading, and I hope I can finish the movie series....