Error 0x51F - Office Pro 2003 Service Pck 2 does not install.

[roameri]

1. I have a P4/XP Pro with latest auto update and OFFICE 2003 Pro with
Service Pack 1. I have McAfee Vers.10 and Webroot Spysweeper but I shut down
both these programs on downloading/installing.
2. I have been downloading the 2003/Service Pack 2 successfully but it does
not INSTALL. " Error 0x51F" . Several trys have proved futile.
3. ( a) As a way out I went on to reinstall/repair OFFICE 2003/PRO from my
CD. Surprisingly that does not go through giving me messages like :

Error 1404 ( Cannot delete Registry file \Software\Classes\CLSID\{A08A033D-IA75-4AB6-A166-FAS02F547959 ) <

and several others like Error 1406 ( Cannot write the value .......).
( b) There is also something about permission to edit the REGISTRY.
(c) Anyways when I went to the REGISTRY I just could not find any of the
files the error messages mentioned.Thanks,
Jamshed.