Emacs 24.4 W32/W64

I'm trying to run Clozure Common Lisp under Emacs / Slime.
Slime lauches CCL and starts the Swank server.
When the process is started by Emacs, I get an error with this backtrace :

? ;Loading #P"c:/Home/.emacs.d/vendor/slime/swank-loader.lisp"...
> Error: Le fournisseur de services demandé n’a pas pu être chargé ou
initialisé.  (error #10106) during socket creation operation in socket
> While executing: SOCKET-ERROR, in process listener(1).
> Type :POP to abort, :R for a list of available restarts.
> Type :? for other options.
1 > :b
 (223996E8) : 0 (SOCKET-ERROR NIL "socket" 10106 NIL) 1133
 (22399750) : 1 (MAKE-TCP-SOCKET :CONNECT :PASSIVE :LOCAL-PORT 0
:LOCAL-HOST "127.0.0.1" :REUSE-ADDRESS T :BACKLOG 5) 429
 (223997D8) : 2 (MAKE-SOCKET :CONNECT :PASSIVE :LOCAL-PORT 0 :LOCAL-HOST
"127.0.0.1" :REUSE-ADDRESS T :BACKLOG 5) 965

The same thing works if I run OpenCL from the console.
How the fact that the process is run from Emacs could
result in an error from make-tcp-socket ?
Conflict with the winsock2 dll which is loaded by both process ?

I have tried many combinations of CCL and emacs :
- Emacs 24.4 32 bits (GNU version)
- Emacs 24.4 64 bits (my version)
- OpenCL 64 bits (official 1.10 version)
- OpenCL 64 bits (compiled by me with the same toolchain used to compile
Emacs)
- OpenCL 32 bits

I couldn't find a working version. Any idea on how to hunt this ?

Best regards,

-- 
Fabrice