MS11-018 Internet Explorer 7.0 Cumulative Security Update (KB2497640) Revised
MS11-018 (KB2497640) for Internet Explorer 7.0 has been revised today to correct an error in Microsoft Update logic. The revision corrects an issue that caused the update to incorrectly report that it was already installed on some Windows XP and Windows Server 2003 platforms where it was not installed. See MS11-018 for details.
Source : WSUS Team Blog