download error messages

I have been trying to reconcile my purchased material to my new computer and noticed that i am missing items. I was able to access most from the cloud and download to my machine, but I have a few songs, videos, a few TV shows and a movie that are either missinf or not downloading. I saw some of the help topics online from Apple and tried to fix them on my own. Hoever, for one of my movies, I attempted to download it 8 times and received various error messages (50, 8387 and the latest being 120). Now for some reason, the little cloud icon has disappeared and I can no longer see the item from the iTunes store in the list of my "purchased" items not currently located on my computer. I figured others may have had the same or similiar issues, so I wanted to post since I've been at this for the past few hours.