Constant "we could not complete your iTunes Store request" messages, even though I'm not using iTunes at the time

With iTunes just sitting in the back doing (supposedly) nothing, every once in a while I get this error message:

we could not complete your itunes store request.

the network connection could not be established.

There was an error in the iTunes Store. Please try again later.

What iTunes store request? I didn't do anything at all, I hadn't touched iTunes in over an hour.

How can i troubleshoot this? it's very distracting, bringing iTunes into focus when I'm doing other things.

thanks

peter