New theme is not working in Respond 6 cms

Question

I copied a out of the box "material" theme and created my new theme based on the same. it gets displayed in list when I am trying to create a new website. but when I select a theme and click on "Create" site it gives me an error.

Lumene error log looks like below:

[2016-10-22 06:44:57] lumen.ERROR: exception 'ErrorException' with message 'Undefined variable: main_content' in C:\xampp\htdocs\respond\app\app\Respond\Models\Page.php:652

I already created a html tag main in my page and also one div which having role="main" but it seems I am still missing something.

can someone guide me for looking at correct issue.

Stacktrace is here :

[2016-10-22 06:47:31] lumen.ERROR: exception 'ErrorException' with message 'Undefined variable: main_content' in C:\xampp\htdocs\respond\app\app\Respond\Models\Page.php:652

Stack trace:

0 C:\xampp\htdocs\respond\app\app\Respond\Models\Page.php(652): Laravel\Lumen\Application->Laravel\Lumen\Concerns\{closure}(8, 'Undefined varia...', 'C:\\xampp\\htdocs...', 652, Array)
1 C:\xampp\htdocs\respond\app\app\Respond\Models\Page.php(507): App\Respond\Models\Page::refreshJSON(Object(App\Respond\Models\User), Object(App\Respond\Models\Site))
2 C:\xampp\htdocs\respond\app\app\Respond\Libraries\Publish.php(167): App\Respond\Models\Page::listAll(Object(App\Respond\Models\User), Object(App\Respond\Models\Site))
3 C:\xampp\htdocs\respond\app\app\Respond\Models\Site.php(162): App\Respond\Libraries\Publish::publishPlugins(Object(App\Respond\Models\User), Object(App\Respond\Models\Site))
4 C:\xampp\htdocs\respond\app\app\Http\Controllers\SiteController.php(44): App\Respond\Models\Site::create('manual9', '/template', 'mygalaxy.shaile...', 'shailesh')
5 [internal function]: App\Http\Controllers\SiteController->create(Object(Illuminate\Http\Request))
6 C:\xampp\htdocs\respond\app\vendor\illuminate\container\Container.php(507): call_user_func_array(Array, Array)
7 C:\xampp\htdocs\respond\app\vendor\laravel\lumen-framework\src\Concerns\RoutesRequests.php(593): Illuminate\Container\Container->call(Array, Array)
8 C:\xampp\htdocs\respond\app\vendor\laravel\lumen-framework\src\Concerns\RoutesRequests.php(560): Laravel\Lumen\Application->callControllerCallable(Array, Array)
9 C:\xampp\htdocs\respond\app\vendor\laravel\lumen-framework\src\Concerns\RoutesRequests.php(533): Laravel\Lumen\Application->callLumenController(Object(App\Http\Controllers\SiteController), 'create', Array)
10 C:\xampp\htdocs\respond\app\vendor\laravel\lumen-framework\src\Concerns\RoutesRequests.php(501): Laravel\Lumen\Application->callControllerAction(Array)
11 C:\xampp\htdocs\respond\app\vendor\laravel\lumen-framework\src\Concerns\RoutesRequests.php(486): Laravel\Lumen\Application->callActionOnArrayBasedRoute(Array)
12 C:\xampp\htdocs\respond\app\vendor\laravel\lumen-framework\src\Concerns\RoutesRequests.php(383): Laravel\Lumen\Application->handleFoundRoute(Array)
13 C:\xampp\htdocs\respond\app\vendor\laravel\lumen-framework\src\Concerns\RoutesRequests.php(636): Laravel\Lumen\Application->Laravel\Lumen\Concerns\{closure}()
14 C:\xampp\htdocs\respond\app\vendor\laravel\lumen-framework\src\Concerns\RoutesRequests.php(389): Laravel\Lumen\Application->sendThroughPipeline(Array, Object(Closure))
15 C:\xampp\htdocs\respond\app\vendor\laravel\lumen-framework\src\Concerns\RoutesRequests.php(334): Laravel\Lumen\Application->dispatch(NULL)
16 C:\xampp\htdocs\respond\app\public\index.php(28): Laravel\Lumen\Application->run()
17 {main}