Vista Update not work

Hello, I believe my Windows update functions no more. My last update for the
Ultimate Version x64 comes from the 28.03.2007 (KB905866). Since then
indicates with the updates function, that my Windows is on the newest state.
Since today I get the announcement from the Defender, that the Deffinitionen
are not more current and during the attempt to carry out an update does agree
I the error report - update not possible - mistake 0x80240029. What can that
be due to? Internet functions 100 %...

To thanks for help and Sorry for my bad English. Many greetings from
Germany...

I have it! Deactivating the automatic update (to deactivate in the update
window to the left of attitudes and everything) and searching for updates
then manually in the Defender. Updates are found and installed. Then search
for Vista Updates, the newest are found. Activating now automatic update
again...

That is a real mistake which Microsoft should soon repair!