bug in update ?

Sirs

I use MiKTeX 2.9 since several years (2011 09 21 on the present PC)
and I update regularly: last time 2015 05 03.
My system is Windows XP SP3 32bits.

When trying a  new update yesterday it failed, with a message upon
copystart_admin failing.
Looking into the miktex\bin\internal directory which contains it and 
comparing with a recent whole disk backup (2015 07 04) I see that 
several files in this directory have disappeared.
I restored all the content of the "Program Files\MikTeX 2.9" directory 
from the backup: same problem.
After a new restoration I succeeded to "thoroughly" uninstall MiKTeX.

I then tried to reinstall it with basic-miktex-2.9.5105.exe (the last 
one downloaded from the site)
It failed giving the following setup-2015-07-30-09-30.log report
------------------------------------------------------------------------

MiKTeX Setup 2.9.4503 Report

Date: Thursday, July 30, 2015
Time: 09:29:38
OS version: Microsoft Windows XP Professional Service Pack 3 (build 2600)
SystemAdmin: yes
PowerUser: false
SharedSetup: yes
Setup path: C:\installs\TeX\MikTeX\basic-miktex-2.9.5105.exe
UserRoots: <none specified>
UserData: <none specified>
UserConfig: <none specified>
CommonRoots: <none specified>
CommonData: <none specified>
CommonConfig: <none specified>

Installation: C:\Program Files\MiKTeX 2.9
Loading package database...
starting package maintenance...
installation directory: "C:\Program Files\MiKTeX 2.9"
package repository: c:\tmp\mik41816
visiting repository c:\tmp\mik41816...
repository type: local package repository
loading lightweight database...
lightweight database digest: 2e1ee451b3ebfd4ef4afc81bbceafc9f
going to install 9562 file(s) (161 package(s))
problem: C:\Program Files\MiKTeX 2.9\miktex/bin\MiKTeX209-core-PS.dll 
does not exist
problem: C:\Program Files\MiKTeX 2.9\miktex/bin\MiKTeX209-core.dll does 
not exist
problem: C:\Program Files\MiKTeX 
2.9\miktex/bin\MiKTeX209-packagemanager-PS.dll does not exist
problem: C:\Program Files\MiKTeX 
2.9\miktex/bin\MiKTeX209-packagemanager.dll does not exist
extracting files from ae.tar.lzma...
extracting files from amscls.tar.lzma...

An error occurred:
   source file: Libraries\MiKTeX\Core\win\winFile.cpp
   source line: 686
   message: Permission denied: C:\Program Files\MiKTeX 
2.9\doc/latex/amscls/amsdtx.pdf
   info: C:\Program Files\MiKTeX 2.9\doc/latex/amscls/amsdtx.pdf

----------------------------------------------------------------------------

Same problem when trying with the net installer downloaded into a 
repository on an external hard drive.

Someone has had the same problem ?
What can I do ?

Maurice

-- 
        Maurice Lombardi
Laboratoire Interdisciplinaire de Physique,
     (ex Spectrometrie Physique)
Universite Joseph Fourier de Grenoble, BP87
38402 Saint Martin d'Heres Cedex     FRANCE
Tel: 33 (0)4 76 51 47 51
Fax: 33 (0)4 76 63 54 95
mailto:[email protected]

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