The service cannot be activated due to a compile-time exception

I have deployed the service WCF

to IIS 7 (Windows Server 2008), but I am getting strange error:

WebHost failed to process a request.
 Sender Information: System.ServiceModel.Activation.HostedHttpRequestAsyncResult/31364015
 Exception: System.ServiceModel.ServiceActivationException: The service '/WCFService.svc' cannot be activated due to an exception during compilation.  The exception message is: Could not load file or assembly 'IHEC.WS.dll, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null' or one of its dependencies. The parameter is incorrect. (Exception from HRESULT: 0x80070057 (E_INVALIDARG)). ---> System.Configuration.ConfigurationErrorsException: Could not load file or assembly 'IHEC.WS.dll, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null' or one of its dependencies. The parameter is incorrect. (Exception from HRESULT: 0x80070057 (E_INVALIDARG)) ---> System.IO.FileLoadException: Could not load file or assembly 'IHEC.WS.dll, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null' or one of its dependencies. The parameter is incorrect. (Exception from HRESULT: 0x80070057 (E_INVALIDARG))
File name: 'IHEC.WS.dll, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null' ---> System.IO.FileLoadException: Could not load file or assembly 'IHEC.WS.dll' or one of its dependencies. The parameter is incorrect. (Exception from HRESULT: 0x80070057 (E_INVALIDARG))
File name: 'IHEC.WS.dll'
WRN: Assembly binding logging is turned OFF.
To enable assembly bind failure logging, set the registry value [HKLM\Software\Microsoft\Fusion!EnableLog] (DWORD) to 1.
Note: There is some performance penalty associated with assembly bind failure logging.
To turn this feature off, remove the registry value [HKLM\Software\Microsoft\Fusion!EnableLog].
   at System.Reflection.Assembly._nLoad(AssemblyName fileName, String codeBase, Evidence assemblySecurity, Assembly locationHint, StackCrawlMark& stackMark, Boolean throwOnFileNotFound, Boolean forIntrospection)
   at System.Reflection.Assembly.nLoad(AssemblyName fileName, String codeBase, Evidence assemblySecurity, Assembly locationHint, StackCrawlMark& stackMark, Boolean throwOnFileNotFound, Boolean forIntrospection)
   at System.Reflection.Assembly.InternalLoad(AssemblyName assemblyRef, Evidence assemblySecurity, StackCrawlMark& stackMark, Boolean forIntrospection)
   at System.Reflection.Assembly.InternalLoad(String assemblyString, Evidence assemblySecurity, StackCrawlMark& stackMark, Boolean forIntrospection)
   at System.Reflection.Assembly.Load(String assemblyString)
   at System.Web.Configuration.CompilationSection.LoadAssemblyHelper(String assemblyName, Boolean starDirective)
   --- End of inner exception stack trace ---
   at System.Web.Configuration.CompilationSection.LoadAssemblyHelper(String assemblyName, Boolean starDirective)
   at System.Web.Configuration.CompilationSection.LoadAllAssembliesFromAppDomainBinDirectory()
   at System.Web.Configuration.CompilationSection.LoadAssembly(AssemblyInfo ai)
   at System.Web.Compilation.BuildManager.GetReferencedAssemblies(CompilationSection compConfig)
   at System.Web.Compilation.WebDirectoryBatchCompiler..ctor(VirtualDirectory vdir)
   at System.Web.Compilation.BuildManager.BatchCompileWebDirectoryInternal(VirtualDirectory vdir, Boolean ignoreErrors)
   at System.Web.Compilation.BuildManager.BatchCompileWebDirectory(VirtualDirectory vdir, VirtualPath virtualDir, Boolean ignoreErrors)
   at System.Web.Compilation.BuildManager.CompileWebFile(VirtualPath virtualPath)
   at System.Web.Compilation.BuildManager.GetVPathBuildResultInternal(VirtualPath virtualPath, Boolean noBuild, Boolean allowCrossApp, Boolean allowBuildInPrecompile)
   at System.Web.Compilation.BuildManager.GetVPathBuildResultWithNoAssert(HttpContext context, VirtualPath virtualPath, Boolean noBuild, Boolean allowCrossApp, Boolean allowBuildInPrecompile)
   at System.Web.Compilation.BuildManager.GetVPathBuildResult(HttpContext context, VirtualPath virtualPath, Boolean noBuild, Boolean allowCrossApp, Boolean allowBuildInPrecompile)
   at System.Web.Compilation.BuildManager.GetCompiledCustomString(String virtualPath)
   at System.ServiceModel.ServiceHostingEnvironment.HostingManager.GetCompiledCustomString(String normalizedVirtualPath)
   at System.ServiceModel.ServiceHostingEnvironment.HostingManager.CreateService(String normalizedVirtualPath)
   at System.ServiceModel.ServiceHostingEnvironment.HostingManager.ActivateService(String normalizedVirtualPath)
   at System.ServiceModel.ServiceHostingEnvironment.HostingManager.EnsureServiceAvailable(String normalizedVirtualPath)
   --- End of inner exception stack trace ---
   at System.ServiceModel.AsyncResult.End[TAsyncResult](IAsyncResult result)
   at System.ServiceModel.Activation.HostedHttpRequestAsyncResult.End(IAsyncResult result)
 Process Name: w3wp
 Process ID: 2616

      

        
        
        
      

    

The strange thing is that the IHEC.WS.dll file is in the bin directory.