The following error shows on when I click on Newsletter on the Admin menu of my site. The same goes for "Site Log, Search Admin, Search Engine-Sitemap" 

Error: Newsletters is currently unavailable. DotNetNuke.Services.Exceptions.ModuleLoadException: External component has thrown an exception. ---> System.Web.HttpCompileException: External component has thrown an exception. at System.Web.Compilation.AssemblyBuilder.Compile() at System.Web.Compilation.BuildProvidersCompiler.PerformBuild() at System.Web.Compilation.BuildManager.CompileWebFile(VirtualPath virtualPath) at System.Web.Compilation.BuildManager.GetVPathBuildResultInternal(VirtualPath virtualPath, Boolean noBuild, Boolean allowCrossApp, Boolean allowBuildInPrecompile, Boolean throwIfNotFound, Boolean ensureIsUpToDate) at System.Web.Compilation.BuildManager.GetVPathBuildResultWithNoAssert(HttpContext context, VirtualPath virtualPath, Boolean noBuild, Boolean allowCrossApp, Boolean allowBuildInPrecompile, Boolean throwIfNotFound, Boolean ensureIsUpToDate) at System.Web.UI.TemplateControl.LoadControl(VirtualPath virtualPath) at DotNetNuke.UI.ControlUtilities.LoadControl[T](TemplateControl containerControl, String ControlSrc) at DotNetNuke.UI.Modules.WebFormsModuleControlFactory.CreateModuleControl(TemplateControl containerControl, ModuleInfo moduleConfiguration) at DotNetNuke.UI.Modules.ModuleControlFactory.LoadModuleControl(TemplateControl containerControl, ModuleInfo moduleConfiguration) at DotNetNuke.UI.Modules.ModuleHost.LoadModuleControl() --- End of inner exception stack trace ---

Any help please?