And below is the reason why:
Description of the SharePoint Server 2007 hotfix package (Coreserver.msp): January 27, 2009 http://support.microsoft.com/default.aspx?scid=kb;EN-US;963022
The resolution is included in February CU. To prevent other customers to also run into the problem described in KB 963022 we have removed the Dec CU package for KB 960011.
We highly recommend to install February CU for WSS and MOSS. http://blogs.msdn.com/sharepoint/archive/2009/03/09/uber-packages-of-february-cumulative-update-are-ready.aspx