iTunes Network Error Code (-9813)

Well, I haven't seen this yet on the Forum... I've recently purchased a new Mac a
2.16 GHz Intel Core 2 Duo iMac. I was fine for a while, not sure what happened... But I'm getting:

iTunes could not connect to the iTunes Store.
An unknown error occured (-9813)

Make sure your network connection is active and try again.

Now I also have a powerbook that I have no trouble conecting to the store and
signing in... Can anyone help me with this?

AppleCoreDesigner.