Error message: 'Cant connect to the itunes store. An unknown error occured (-3212) please check you have an active internet connection and try again'. Help !

Can someone help me please ? I was using itunes (downloading albums etc) just half an hour ago. I had a pop up asking me if i'd like to download the latest version of itunes, which i accepted. When the update had finshed downloading, i then restarted my computer, as i usually would. Tried to re access the itunes store, and received the following error message: 'Cant connect to the itunes store. An unknown error occurred (-3212) please check you have an active internet connection and try again.

Needless to say, i have an active internet connection and cant see any reason why this would be happening, it has never happened before ?

Any help would be appreciated.