IIS7 Imansible concedere richieste di authorization minime

Ottengo questo errore quando utilizzo FileHelpers.dll, ma il mio IIS è impostato su Livello di attendibilità totale quindi non dovrebbe essere in questo modo

Questa è la traccia dello stack completo:

[PolicyException: Required permissions cannot be acquired.] System.Security.SecurityManager.ResolvePolicy(Evidence evidence, PermissionSet reqdPset, PermissionSet optPset, PermissionSet denyPset, PermissionSet& denied, Boolean checkExecutionPermission) +10238142 System.Security.SecurityManager.ResolvePolicy(Evidence evidence, PermissionSet reqdPset, PermissionSet optPset, PermissionSet denyPset, PermissionSet& denied, Int32& securitySpecialFlags, Boolean checkExecutionPermission) +97 [FileLoadException: Could not load file or assembly 'FileHelpers, Version=2.0.0.0, Culture=neutral, PublicKeyToken=3e0c08d59cc3d657' or one of its dependencies. Failed to grant minimum permission requests. (Exception from HRESULT: 0x80131417)] System.Reflection.Assembly._nLoad(AssemblyName fileName, String codeBase, Evidence assemblySecurity, Assembly locationHint, StackCrawlMark& stackMark, Boolean throwOnFileNotFound, Boolean forIntrospection) +0 System.Reflection.Assembly.InternalLoad(AssemblyName assemblyRef, Evidence assemblySecurity, StackCrawlMark& stackMark, Boolean forIntrospection) +416 System.Reflection.Assembly.InternalLoad(String assemblyString, Evidence assemblySecurity, StackCrawlMark& stackMark, Boolean forIntrospection) +166 System.Reflection.Assembly.Load(String assemblyString) +35 System.Web.Configuration.CompilationSection.LoadAssemblyHelper(String assemblyName, Boolean starDirective) +190 [ConfigurationErrorsException: Could not load file or assembly 'FileHelpers, Version=2.0.0.0, Culture=neutral, PublicKeyToken=3e0c08d59cc3d657' or one of its dependencies. Failed to grant minimum permission requests. (Exception from HRESULT: 0x80131417)] System.Web.Configuration.CompilationSection.LoadAssemblyHelper(String assemblyName, Boolean starDirective) +11207304 System.Web.Configuration.CompilationSection.LoadAllAssembliesFromAppDomainBinDirectory() +388 System.Web.Configuration.CompilationSection.LoadAssembly(AssemblyInfo ai) +232 System.Web.Configuration.AssemblyInfo.get_AssemblyInternal() +48 System.Web.Compilation.BuildManager.GetReferencedAssemblies(CompilationSection compConfig) +210 System.Web.Compilation.BuildProvidersCompiler..ctor(VirtualPath configPath, Boolean supportLocalization, String outputAssemblyName) +76 System.Web.Compilation.ApplicationBuildProvider.GetGlobalAsaxBuildResult(Boolean isPrecompiledApp) +283 System.Web.Compilation.BuildManager.CompileGlobalAsax() +50 System.Web.Compilation.BuildManager.EnsureTopLevelFilesCompiled() +676 [HttpException (0x80004005): Could not load file or assembly 'FileHelpers, Version=2.0.0.0, Culture=neutral, PublicKeyToken=3e0c08d59cc3d657' or one of its dependencies. Failed to grant minimum permission requests. (Exception from HRESULT: 0x80131417)] System.Web.Compilation.BuildManager.ReportTopLevelCompilationException() +76 System.Web.Compilation.BuildManager.EnsureTopLevelFilesCompiled() +1012 System.Web.Hosting.HostingEnvironment.Initialize(ApplicationManager appManager, IApplicationHost appHost, IConfigMapPathFactory configMapPathFactory, HostingEnvironmentParameters hostingParameters) +1025 [HttpException (0x80004005): Could not load file or assembly 'FileHelpers, Version=2.0.0.0, Culture=neutral, PublicKeyToken=3e0c08d59cc3d657' or one of its dependencies. Failed to grant minimum permission requests. (Exception from HRESULT: 0x80131417)] System.Web.HttpRuntime.FirstRequestInit(HttpContext context) +11301302 System.Web.HttpRuntime.EnsureFirstRequestInit(HttpContext context) +88 System.Web.HttpRuntime.ProcessRequestNotificationPrivate(IIS7WorkerRequest wr, HttpContext context) +4338644