I have exactly the same issue. Can not login to my Google Adsense account I created a few years back. It was working perfectly with iWeb'08, but now in iWeb'09 every time I try to log in it tells me that 'The information you provided did not match any Google AdSense account.' Account information I enter is exactly the same as in my Google profile.
I just phoned up Apple Support UK about this issue. They told me to follow Mario Batz's solution
Mario Batz wrote:
had to remove the apple Adsense boxes from my site and republish it entirely, add the html snippets with the google code and publish again. then the adds worked.
Unfortunately using HTML snippets omits the whole point of iWeb AdSense integration ;/ I've asked support rep. to pass on information about this issue to relevant department, so hopefully Apple/Google will come up with a solution soon.
Message was edited by: mac_ivan