Impossible installer ie8 beta.

Bonjour,
Cela fait quelques jours que je tente, sans succès même en mode sans échec,
d'installer la version française de ie8 beta.
L'installation se termine systématiquement en affichant le message suivant:
"Internet Explorer 8 n'a pas pu être installée. Vous devez redémarrer votre
système pour vérifier que toutes les modifications apportées à votre système
sont annulées.
Une fois que vous redémarrez, suivez le raccourci « Internet Explorer
Résolution des problèmes » sur votre Bureau pour obtenir plus d'informations."
J'utilise WinXP pro sp3 et ie7 et ils sont tout à fait à jour et j'ai les
droits d'administrateur..
Merci de m'éclairer.


A toutes fins utiles, voici la log d'installation:[ie8.log]
0.219:=================================================
0.219: 2008/12/17 19:46:14.953 (local)
0.219: c:\1f6e4cb6a567116beb05ab6b2f11ddf9\update\update.exe (version
6.3.15.0)
0.235: Hotfix started with following command line: /quiet /norestart /er
/log:C:\WINDOWS
0.266: In Function GetReleaseSet, line 1240, RegQueryValueEx failed with
error 0x2
0.297: IECUSTOM: Scanning for proper registry permissions...
0.641: IECUSTOM: Unwriteable key
HKCR\Interface\{34A715A0-6587-11D0-924A-0020AFC7AC4D}
0.641: IECUSTOM: Unwriteable key
HKCR\Interface\{34A715A0-6587-11D0-924A-0020AFC7AC4D}\ProxyStubClsid
0.641: IECUSTOM: Unwriteable key
HKCR\Interface\{34A715A0-6587-11D0-924A-0020AFC7AC4D}
0.641: IECUSTOM: Unwriteable key
HKCR\Interface\{34A715A0-6587-11D0-924A-0020AFC7AC4D}\ProxyStubClsid32
0.641: IECUSTOM: Unwriteable key
HKCR\Interface\{34A715A0-6587-11D0-924A-0020AFC7AC4D}
0.641: IECUSTOM: Unwriteable key
HKCR\Interface\{34A715A0-6587-11D0-924A-0020AFC7AC4D}\TypeLib
0.641: IECUSTOM: Unwriteable key
HKCR\Interface\{34A715A0-6587-11D0-924A-0020AFC7AC4D}
0.641: IECUSTOM: Unwriteable key
HKCR\Interface\{34A715A0-6587-11D0-924A-0020AFC7AC4D}\TypeLib
0.641: IECUSTOM: Unwriteable key
HKCR\Interface\{34A715A0-6587-11D0-924A-0020AFC7AC4D}
0.828: IECUSTOM: Scanning for proper registry permissions...
0.953: IECUSTOM: Scanning for proper registry permissions...
1.157: IECUSTOM: Unwriteable key
HKCR\Interface\{34A715A0-6587-11D0-924A-0020AFC7AC4D}
1.219: IECUSTOM: Backing up registry permissions...
1.297: IECUSTOM: Finished backing up registry permissions...
1.297: IECUSTOM: Setting new registry permissions...
1.344: IECUSTOM: Unable to clear DACLs
HKCR\Interface\{34A715A0-6587-11D0-924A-0020AFC7AC4D}
1.344: IECUSTOM: Finished setting new registry permissions...
1.344: IECUSTOM: An error occured verifying registry permissions. ERROR:
0x80070534
1.344: DoInstallation: CustomizeCall Failed: 0x3f5
1.344: IECUSTOM: Restoring registry permissions...
1.344: IECUSTOM: Finished restoring registry permissions...
1.375: Impossible d'écrire la clé du Registre de configuration.
1.375: L'installation du Internet Explorer 8 ne s'est pas terminée.
1.375: Update.exe extended error code = 0x3f5
0.172:=================================================
0.172: 2008/12/17 20:10:47.078 (local)
0.172: c:\18a11941321cedf51d\update\update.exe (version 6.3.15.0)
0.219: Hotfix started with following command line: /quiet /norestart /er
/log:C:\WINDOWS
0.219: In Function GetReleaseSet, line 1240, RegQueryValueEx failed with
error 0x2
0.266: IECUSTOM: Scanning for proper registry permissions...
0.594: IECUSTOM: Unwriteable key
HKCR\Interface\{34A715A0-6587-11D0-924A-0020AFC7AC4D}
0.594: IECUSTOM: Unwriteable key
HKCR\Interface\{34A715A0-6587-11D0-924A-0020AFC7AC4D}\ProxyStubClsid
0.594: IECUSTOM: Unwriteable key
HKCR\Interface\{34A715A0-6587-11D0-924A-0020AFC7AC4D}
0.594: IECUSTOM: Unwriteable key
HKCR\Interface\{34A715A0-6587-11D0-924A-0020AFC7AC4D}\ProxyStubClsid32
0.594: IECUSTOM: Unwriteable key
HKCR\Interface\{34A715A0-6587-11D0-924A-0020AFC7AC4D}
0.594: IECUSTOM: Unwriteable key
HKCR\Interface\{34A715A0-6587-11D0-924A-0020AFC7AC4D}\TypeLib
0.594: IECUSTOM: Unwriteable key
HKCR\Interface\{34A715A0-6587-11D0-924A-0020AFC7AC4D}
0.594: IECUSTOM: Unwriteable key
HKCR\Interface\{34A715A0-6587-11D0-924A-0020AFC7AC4D}\TypeLib
0.594: IECUSTOM: Unwriteable key
HKCR\Interface\{34A715A0-6587-11D0-924A-0020AFC7AC4D}
0.781: IECUSTOM: Scanning for proper registry permissions...
0.922: IECUSTOM: Scanning for proper registry permissions...
1.110: IECUSTOM: Unwriteable key
HKCR\Interface\{34A715A0-6587-11D0-924A-0020AFC7AC4D}
1.172: IECUSTOM: Backing up registry permissions...
1.172: IECUSTOM: Finished backing up registry permissions...
1.172: IECUSTOM: Setting new registry permissions...
1.188: IECUSTOM: Unable to clear DACLs
HKCR\Interface\{34A715A0-6587-11D0-924A-0020AFC7AC4D}
1.188: IECUSTOM: Finished setting new registry permissions...
1.188: IECUSTOM: An error occured verifying registry permissions. ERROR:
0x80070534
1.188: DoInstallation: CustomizeCall Failed: 0x3f5
1.188: IECUSTOM: Restoring registry permissions...
1.188: IECUSTOM: Finished restoring registry permissions...
1.203: Impossible d'écrire la clé du Registre de configuration.
1.203: L'installation du Internet Explorer 8 ne s'est pas terminée.
1.203: Update.exe extended error code = 0x3f5