How do I resume my download?

I tried to buy a movie on iTunes, and the purchase went through. But as the movie was downloading, my computer died. I restarted the computer, but when I tried to resume the download, it said that error (-50) occurred. The internet connection was fine, and I tried everything that this article recommended, but the same window keeps popping up about the error. I even tried repurchasing it, but it told me that I already purchased the item, as I expected. What am I supposed to do now? How do I get the movie to finish downloading? Please help!? 😕