http://bugs.winehq.org/show_bug.cgi?id=18384
--- Comment #18 from guillaume.laforie@laposte.net 2009-05-30 13:30:27 --- note that in the trace
Content-Type: application/x-www-form-urlencoded\n\nContent-Length: 343 <<<<<
it should be IMHO
Content-Type: application/x-www-form-urlencoded\r\nContent-Length: 343 <<<<<
that may explain the internal error on the serveur