我的 laravel 4 项目有时会在错误日志中打印如下错误：
exception 'Symfony\Component\HttpKernel\Exception\NotFoundHttpException' in /var/www/html/projectname/bootstrap/compiled.php:5336 Stack trace: #0 /var/www/html/projectname/bootstrap/compiled.php(4685):
Illuminate\Routing\RouteCollection->match(Object(Illuminate\Http\Request)) #1 /var/www/html/projectname/bootstrap/compiled.php(4673):
Illuminate\Routing\Router->findRoute(Object(Illuminate\Http\Request)) #2 /var/www/html/projectname/bootstrap/compiled.php(4665):
Illuminate\Routing\Router->dispatchToRoute(Object(Illuminate\Http\Request)) #3 /var/www/html/projectname/bootstrap/compiled.php(706):
Illuminate\Routing\Router->dispatch(Object(Illuminate\Http\Request)) #4 /var/www/html/projectname/bootstrap/compiled.php(687):
Illuminate\Foundation\Application->dispatch(Object(Illuminate\Http\Request)) #5 /var/www/html/projectname/bootstrap/compiled.php(1146):
Illuminate\Foundation\Application->handle(Object(Illuminate\Http\Request), 1, true) #6 /var/www/html/projectname/bootstrap/compiled.php(7308):
Illuminate\Http\FrameGuard->handle(Object(Illuminate\Http\Request), 1, true) #7 /var/www/html/projectname/bootstrap/compiled.php(7905):
Illuminate\Session\Middleware->handle(Object(Illuminate\Http\Request), 1, true) #8 /var/www/html/projectname/bootstrap/compiled.php(7852):
Illuminate\Cookie\Queue->handle(Object(Illuminate\Http\Request), 1, true) #9 /var/www/html/projectname/bootstrap/compiled.php(10872):
Illuminate\Cookie\Guard->handle(Object(Illuminate\Http\Request), 1, true) #10 /var/www/html/projectname/bootstrap/compiled.php(648):
Stack\StackedHttpKernel->handle(Object(Illuminate\Http\Request)) #11 /var/www/html/projectname/public/index.php(65):
Illuminate\Foundation\Application->run() #12
{main}
我无法解决问题。这是什么原因？任何帮助，将不胜感激。谢谢。