Thanks very much for your response. It was indeed missing Description.txt. I got it in place. Then I got an reference assembly failing to load error for Autofac. I compared the version of it with the same in another plugin (Amazon Pay). I saw it is different and TwitterAuth had Local copy = True for for both Autofac and Autofac.Integration.Mvc. I updated both Autofac and Autofac.Integration.Mvc to match Amazon Pay plugin's referenced ones versions (3.5.2 and 3.3.4) and made them Local Copy = false. It solved all the initial problems and Twitter Auth Plugin started appearing in Manage Plugins page.
I installed it. I restarted the app. I clicked "Update resources" button. That went all fine. But when I click "Configure" I got the error below. But all other plugins (i.e. facebook, AmazonPay) are responding to Configure button click fine. Only newly installed TwitterAuth plugin has this problem below.
An unknown error occurred when calling a plugin. Please refer to the following message for details.
System.Web.HttpException (0x80004005): Execution of the child request failed. Please examine the InnerException for more information. ---> System.Web.HttpException (0x80004005): The controller for path '/Admin/Plugin/ConfigurePlugin' was not found or does not implement IController.
at System.Web.Mvc.DefaultControllerFactory.GetControllerInstance(RequestContext requestContext, Type controllerType)
at System.Web.Mvc.DefaultControllerFactory.CreateController(RequestContext requestContext, String controllerName)
at System.Web.Mvc.MvcHandler.ProcessRequestInit(HttpContextBase httpContext, IController& controller, IControllerFactory& factory)
at System.Web.Mvc.MvcHandler.BeginProcessRequest(HttpContextBase httpContext, AsyncCallback callback, Object state)
at System.Web.Mvc.HttpHandlerUtil.ServerExecuteHttpHandlerWrapper.Wrap[TResult](Func`1 func)
at System.Web.Mvc.HttpHandlerUtil.ServerExecuteHttpHandlerWrapper.Wrap[TResult](Func`1 func)
at System.Web.HttpServerUtility.ExecuteInternal(IHttpHandler handler, TextWriter writer, Boolean preserveForm, Boolean setPreviousPage, VirtualPath path, VirtualPath filePath, String physPath, Exception error, String queryStringOverride)
at System.Web.HttpServerUtility.Execute(IHttpHandler handler, TextWriter writer, Boolean preserveForm, Boolean setPreviousPage)
at System.Web.HttpServerUtility.Execute(IHttpHandler handler, TextWriter writer, Boolean preserveForm)
at System.Web.Mvc.Html.ChildActionExtensions.ActionHelper(HtmlHelper htmlHelper, String actionName, String controllerName, RouteValueDictionary routeValues, TextWriter textWriter)
at System.Web.Mvc.Html.ChildActionExtensions.Action(HtmlHelper htmlHelper, String actionName, String controllerName, RouteValueDictionary routeValues)
at ASP._Page_Administration_Views_Plugin_ConfigurePlugin_cshtml.Execute() in f:\kushil\iZDOT\PublishedFromCode\Administration\Views\Plugin\ConfigurePlugin.cshtml:line 25