WebLogic installation on a non-English server machine

I often install WebLogic environment for various companies.  Most of them are using Oracle Linux, or other Linux variants, and a minority use MS Windows Server.
They are all installed in English, but last week I had a Wallonian customer that installed their Windows machine in French...

So, I installed their the WebLogic software and the ADF libraries and everything seemed to work fine:
no errors during installation and configuration, admin server started well.
But when starting the managed server, it generated a lot of these messages:

####<09-mai-2014 9 h 05 min 23 s CEST> <Error> <Socket> <CH1WL01> <AdfServer> <ExecuteThread: '0' for queue: 'weblogic.socket.Muxer'> <<WLS Kernel>> <> <3bef1877-e26f-4f29-b579-34da429a7b65-00000013> <1399619123679> <BEA-000403> <IOException occurred on socket: Socket[addr=/10.1.0.74,port=52704,localport=7003]
 java.io.IOException: Une connexion établie a été abandonnée par un logiciel de votre ordinateur hôte.
java.io.IOException: Une connexion établie a été abandonnée par un logiciel de votre ordinateur hôte
 at sun.nio.ch.SocketDispatcher.read0(Native Method)
 at sun.nio.ch.SocketDispatcher.read(SocketDispatcher.java:43)
 at sun.nio.ch.IOUtil.readIntoNativeBuffer(IOUtil.java:223)
 at sun.nio.ch.IOUtil.read(IOUtil.java:197)
 at sun.nio.ch.SocketChannelImpl.read(SocketChannelImpl.java:379)
 at weblogic.socket.NIOSocketMuxer$NIOInputStream.read(NIOSocketMuxer.java:747)
 at weblogic.socket.NIOSocketMuxer$NIOInputStream.read(NIOSocketMuxer.java:733)
 at weblogic.socket.SocketMuxer.readFromSocket(SocketMuxer.java:1017)
 at weblogic.socket.NIOSocketMuxer.readFromSocket(NIOSocketMuxer.java:642)
 at weblogic.socket.SocketMuxer.readReadySocketOnce(SocketMuxer.java:951)
 at weblogic.socket.SocketMuxer.readReadySocket(SocketMuxer.java:928)
 at weblogic.socket.NIOSocketMuxer.process(NIOSocketMuxer.java:507)
 at weblogic.socket.NIOSocketMuxer.processSockets(NIOSocketMuxer.java:473)
 at weblogic.socket.SocketReaderRequest.run(SocketReaderRequest.java:30)
 at weblogic.socket.SocketReaderRequest.execute(SocketReaderRequest.java:43)
 at weblogic.kernel.ExecuteThread.execute(ExecuteThread.java:147)
 at weblogic.kernel.ExecuteThread.run(ExecuteThread.java:119)
> 
####<09-mai-2014 9 h 05 min 23 s CEST> <Error> <HTTP> <CH1WL01> <AdfServer> <ExecuteThread: '0' for queue: 'weblogic.socket.Muxer'> <<WLS Kernel>> <> <3bef1877-e26f-4f29-b579-34da429a7b65-00000013> <1399619123679> <BEA-101083> <Connection failure.
java.io.IOException: Une connexion établie a été abandonnée par un logiciel de votre ordinateur hôte
 at sun.nio.ch.SocketDispatcher.read0(Native Method)
 at sun.nio.ch.SocketDispatcher.read(SocketDispatcher.java:43)
 at sun.nio.ch.IOUtil.readIntoNativeBuffer(IOUtil.java:223)
 at sun.nio.ch.IOUtil.read(IOUtil.java:197)
 at sun.nio.ch.SocketChannelImpl.read(SocketChannelImpl.java:379)
 at weblogic.socket.NIOSocketMuxer$NIOInputStream.read(NIOSocketMuxer.java:747)
 at weblogic.socket.NIOSocketMuxer$NIOInputStream.read(NIOSocketMuxer.java:733)
 at weblogic.socket.SocketMuxer.readFromSocket(SocketMuxer.java:1017)
 at weblogic.socket.NIOSocketMuxer.readFromSocket(NIOSocketMuxer.java:642)
 at weblogic.socket.SocketMuxer.readReadySocketOnce(SocketMuxer.java:951)
 at weblogic.socket.SocketMuxer.readReadySocket(SocketMuxer.java:928)
 at weblogic.socket.NIOSocketMuxer.process(NIOSocketMuxer.java:507)
 at weblogic.socket.NIOSocketMuxer.processSockets(NIOSocketMuxer.java:473)
 at weblogic.socket.SocketReaderRequest.run(SocketReaderRequest.java:30)
 at weblogic.socket.SocketReaderRequest.execute(SocketReaderRequest.java:43)
 at weblogic.kernel.ExecuteThread.execute(ExecuteThread.java:147)
 at weblogic.kernel.ExecuteThread.run(ExecuteThread.java:119)
> 

And when deploying a test application on the server, it gave no response in my browser...

Fortunately, I found a patch on My Oracle Support to solve this.
I applied patch 18373180 (available for Oracle WebLogic 12c R2) through OPatch and did not encounter anymore this error...