file exception error lavarel

[2014-09-29 09:17:06] production.ERROR: exception 'Symfony\Component\HttpFoundation\File\Exception\FileException' with message 'The file "om.jpg" was not uploaded due to an unknown error.' in /var/www/vendor/symfony/http-foundation/Symfony/Component/HttpFoundation/File/UploadedFile.php:251
Stack trace:
#0 /var/www/app/controllers/BroadcastController.php(43): Symfony\Component\HttpFoundation\File\UploadedFile->move()
#1 [internal function]: BroadcastController->postIndex()
#2 /var/www/vendor/laravel/framework/src/Illuminate/Routing/Controller.php(231): call_user_func_array(Array, Array)
#3 /var/www/bootstrap/compiled.php(5784): Illuminate\Routing\Controller->callAction('postIndex', Array)
#4 /var/www/bootstrap/compiled.php(5772): Illuminate\Routing\ControllerDispatcher->call(Object(BroadcastController), Object(Illuminate\Routing\Route), 'postIndex')
#5 /var/www/bootstrap/compiled.php(4971): Illuminate\Routing\ControllerDispatcher->dispatch(Object(Illuminate\Routing\Route), Object(Illuminate\Http\Request), 'BroadcastContro...', 'postIndex')
#6 [internal function]: Illuminate\Routing\Router->Illuminate\Routing\{closure}()
#7 /var/www/bootstrap/compiled.php(5330): call_user_func_array(Object(Closure), Array)
#8 /var/www/bootstrap/compiled.php(4996): Illuminate\Routing\Route->run(Object(Illuminate\Http\Request))
#9 /var/www/bootstrap/compiled.php(4984): Illuminate\Routing\Router->dispatchToRoute(Object(Illuminate\Http\Request))
#10 /var/www/bootstrap/compiled.php(717): Illuminate\Routing\Router->dispatch(Object(Illuminate\Http\Request))
#11 /var/www/bootstrap/compiled.php(698): Illuminate\Foundation\Application->dispatch(Object(Illuminate\Http\Request))
#12 /var/www/vendor/barryvdh/laravel-debugbar/src/Barryvdh/Debugbar/Middleware.php(34): Illuminate\Foundation\Application->handle(Object(Illuminate\Http\Request), 1, true)
#13 /var/www/bootstrap/compiled.php(7706): Barryvdh\Debugbar\Middleware->handle(Object(Illuminate\Http\Request), 1, true)
#14 /var/www/bootstrap/compiled.php(8309): Illuminate\Session\Middleware->handle(Object(Illuminate\Http\Request), 1, true)
#15 /var/www/bootstrap/compiled.php(8256): Illuminate\Cookie\Queue->handle(Object(Illuminate\Http\Request), 1, true)
#16 /var/www/bootstrap/compiled.php(10895): Illuminate\Cookie\Guard->handle(Object(Illuminate\Http\Request), 1, true)
#17 /var/www/bootstrap/compiled.php(659): Stack\StackedHttpKernel->handle(Object(Illuminate\Http\Request))
#18 /var/www/public/index.php(49): Illuminate\Foundation\Application->run()
#19 {main} [] [