We could not complete your iTunes Store request. An unknown error occurred (-42408)

What does this mean? I just recieved my Ipod touch 5g, today. And i can't sync to itunes? At first i was able to sync with Itunes, to put songs and my old Apps in it. And now I can't? I tried it just now and it says, "this computer is no longer authorized for apps Installed on the Ipod "------- iPod". Would you like to authorize this computer for items purchased from the iTunes Store?" And if click "authorize", type in my information then i get what is in the title, "We could not complete your iTunes Store request. An unknown error occurred (-42408)"

What can i do to fix this? Cause im quite adgitated now.. I can't add music, pictures, contacts, etc, through iTunes. I can manually add Apps on it, through the App Store, BUT when i try to sync it, it wants me to authorize my computer and i can't! And if i click "Don't Authorize" its gonna erase the Apps that i just downloaded, and along with the data!