Elina, like the others said. Those files are virus free, trust me if they were not. 9 Out of 10 one or two players would have posted on the forums, saying that the items files have viruses. Plus Mediafire is a free hosting sharing file (with a few features you will have to buy in order to use.) That should give you a sign that the site does not have any viruses, and if it does like Evil shocked said: "The staff would never allow more people to have it otherwise. The download is safe, I promise. If you have further concerns, then I'd suggest PMing a member of staff."
The people who posted those virus links up may get banned from media fire, and if the mods find out i'm sure they will deal with the virus maker as well. You can tell what sites are mischief looking and those that are not. Regarding to your questions about you not seeing the items. Have you download them already? But you do not see them? That means you did not install the items in correctly, Try looking at the read me in the folder of the file you download, that could help or the link Cloud fish provided for you. Or can you not see the download at all? Did you even go to the link that was posted? The item pack download is still there.