It meens u have not define the conroller called IndexController or you didnt load the Controllers,you can put your publc/index.php code on the page when you reply,may be i can find the error
Just like this:
if you have defined namespce,you can
$loader = new \Phalcon\Loader();
$loader->registerNamespaces(array(
'Brand\Models' => $config->application->modelsDir,
'Brand\Plugins' => $config->application->pluginsDir,
'Brand\Library' => $config->application->libraryDir
));
or not,you can
$loader->registerDirs(array(
$config->application->controllersDir,
))
Becasue i have create more modules for my project,so u can choose a better way to solve your problem