And below is the reason why:

Check:

Description of the SharePoint Server 2007 hotfix package (Coreserver.msp): January 27, 2009
http://support.microsoft.com/default.aspx?scid=kb;EN-US;963022

Issues that this hotfix package fixes
  • After you apply update 959637 or update 960011, the daily scheduled incremental crawl and full crawl never run.
  • You intermittently find errors in the crawl logs for full or incremental crawls of SharePoint content. The errors resemble the following:

    0x8002802B (TYPE_E_ELEMENTNOTFOUND.

 

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