If like me you are doing your Christmas card labels at the moment and you use a tablet PC then watch out for this bug.
You run the mail merge wizard from Outlook (or Word) but when you update labels, it only puts the address block on the first two and last two label boxes on each page, leaving the rest blank. very weird.
Turns out this only happens on a Tablet PC and is a known bug with a fairly easy work involving using the Tablet PC input at stage 4-6 of the mail merge wizard. Might save someone some time. And no it's not fixed in sp1 :-(