My WordPress 1.5.1 Upgrade

Yesterday night when WordPress 1.5.1 got released, I downloaded and upgraded 2:48AM to it. Everything is running smoothly except for one minor issue I have. When people comment on 2:48AM I get an email with the name of the person who commented under name, and the title of the email would be related to the post. After upgrading to 1.5.1 I get an email still but the name is now (unknown sender). I don’t know where I went wrong with the upgrade or if this is connected to my skin. But it sucks!

update: just tried it with 2 different skins, same problem. Must mean I messed up witht he upgrade somewhere…