Although there isn't a "Publisher" update that I know of, there are a couple of other similar sounding updates. See the two below:
Windows Installer 3.1 (v2) is available
Package Installer for Windows
Both of the items above are new updates for Windows XP.
Hope this helps.
XP Home Edition with Google as home page on IE
I while back I had a problem with AVG installations because Windows Update began running at the same time. As a result, I cancelled automatic Windows Update. Now, checking for updates, Windows asks me if I want to have installed the "Microsoft Windows Publisher". Please advise what that is. Then, Windows gave another message that there was a problem and to delete temp files then re-open IE. I've never had this from Windows Update before. Help! :o)