iPhone Cannot Make or Receive Calls. Restore Needed.

Hi,

Got the "iPhone Cannot Make or Receive Calls. Restore Needed." message and just wondered whether really need to restore? Seen as 4.2 is about to come out, I don't want to push my internet usage much further (because I will have to download 4.1 again, because something will go horrifically wrong, like always)... it's also a huge waste of time...

So, is this message real, or just a dodgy pop up, I immediately rang my home phone and it worked, does this mean it works? Or, is this a temperamental issue or what? Obviously I will restore if I have to, and I know I probably should, I just don't want to if I don't have to (if you get what I mean)!

Thanks,
Jamie