Impossible d'initialiser les parametres globaux

System.Web.Services.Protocols.SoapException: Server was unable to process request. ---> Invalid length for a Base-64 char array. at System.Web.Services.Protocols.SoapHttpClientProtocol.ReadResponse(SoapClientMessage message, WebResponse response, Stream responseStream, Boolean asyncCall) at System.Web.Services.Protocols.SoapHttpClientProtocol.Invoke(String methodName, Object[] parameters) at OpenSystem.OsServicesClients.OsServicesScenario.OsSoap.SoapWeb.InitialiseContexte(ContexteCaddie Contexte, String CleSession) at OpenSystem.OsSites.OsRecherche.Web.CreeParametresEtape(Int32 OrdreEtape, String CleSession, String IdLangue, VarWidgetSession SessionWidget) at OpenSystem.OsSites.OsRecherche.Index.InitialiseGlobales(Int32 num, ParametresXml Globals, String refsession) at OpenSystem.OsSites.OsRecherche.Index.Initialisation(Int32 idrechscenario)