CI Route Issue Not Getting Variable - codeigniter

Question

I'm having an issue with this route and not sure what my problem is exactly.
My page is located at http://www.kansasoutlawwrestling.com/kowmanager/pmsystem/viewmessage/1 where 1 is the message id.
I set up a route to look like
$route['pmsystem/viewmessage/(:num)'] = 'pmsystem/viewmessage/$1';
and I'm still getting a error message like this
A PHP Error was encountered
Severity: Warning
Message: Missing argument 1 for Pmsystem::viewmessage()
Filename: controllers/pmsystem.php
Line Number: 76
// View A Message
function viewmessage($message_id)
{
//Config Defaults Start
$msgBoxMsgs = array();//msgType = dl, info, warn, note, msg
$cssPageAddons = '';//If you have extra CSS for this view append it here
$jsPageAddons = '<script src='.base_url().'../assets/js/cpanel/personalmessages.js></script><script src='.base_url().'assets/js/mylibs/jwysiwyg/jquery.wysiwyg.js></script>';//If you have extra JS for this view append it here
$metaAddons = '';//Sometimes there is a need for additional Meta Data such in the case of Facebook addon's
$siteTitle = '';//alter only if you need something other than the default for this view.
//Config Defaults Start
//examples of how to use the message box system (css not included).
//$msgBoxMsgs[] = array('msgType' => 'dl', 'theMsg' => 'This is a Blank Message Box...');
/**********************************************************Your Coding Logic Here, Start*/
// Checks to see if a session is active for user and shows corresponding view page
if (!$this->loggedin->chkLoginStatus() === FALSE)
{
if( ! $this->uri->segment(3))
{
redirect('error', 'refresh');
}
}
else
{
redirect('login', 'refresh');
}
$bodyContent = 'viewpm';//which view file
$bodyType = "full";//type of template
/***********************************************************Your Coding Logic Here, End*/
//Double checks if any default variables have been changed, Start.
//If msgBoxMsgs array has anything in it, if so displays it in view, else does nothing.
if(count($msgBoxMsgs) !== 0)
{
$msgBoxes = $this->msgboxes->buildMsgBoxesOutput(array('display' => 'show', 'msgs' =>$msgBoxMsgs));
}
else
{
$msgBoxes = array('display' => 'none');
}
if($siteTitle == '')
{
$siteTitle = $this->metatags->SiteTitle(); //reads
}
//Double checks if any default variables have been changed, End.
$this->data['msgBoxes'] = $msgBoxes;
$this->data['cssPageAddons'] = $cssPageAddons;//if there is any additional CSS to add from above Variable this will send it to the view.
$this->data['jsPageAddons'] = $jsPageAddons;//if there is any addictional JS to add from the above variable this will send it to the view.
$this->data['metaAddons'] = $metaAddons;//if there is any addictional meta data to add from the above variable this will send it to the view.
$this->data['pageMetaTags'] = $this->metatags->MetaTags();//defaults can be changed via models/metatags.php
$this->data['siteTitle'] = $siteTitle;//defaults can be changed via models/metatags.php
$this->data['bodyType'] = $bodyType;
$this->data['bodyContent'] = $bodyContent;
$this->data['user_data'] = $this->users->getUserByUserId($this->session->userdata('user_id'));
$this->data['users'] = $this->loggedin->getUserList();
$this->data['personal_messages'] = array($this->pmmodel->getTotalMessages($this->session->userdata('user_id')), $this->pmmodel->getTotalUnreadMessages($this->session->userdata('user_id')), $this->pmmodel->getLast5Messages($this->session->userdata('user_id')));
$this->data['messages'] = array($this->pmmodel->getInboxMessages($this->session->userdata('user_id')), $this->pmmodel->getSentMessages($this->session->userdata('user_id')));
//$this->data['message_data'] = $this->pmmodel->getPmMessage($this->uri->segment(3));
$this->load->view('cpanel/index', $this->data);
}
UPDATE
// Checks to see if a session is active for user and shows corresponding view page
if (!$this->loggedin->chkLoginStatus() === FALSE)
{
if (!is_numeric($this->uri->segment(3)))
{
$this->data['message_data'] = 'Invalid message id!';
}
else
{
$this->data['message_data'] = $this->pmmodel->getPmMessage($this->uri->segment(3));
}
$bodyContent = 'viewpm';//which view file
}
else
{
redirect('login', 'refresh');
}
$bodyType = "full";//type of template

Answer 1

This route is unnecessary - it doesn't change anything.
$route['pmsystem/viewmessage/(:num)'] = 'pmsystem/viewmessage/$1';
You can remove that route. The problem is here:
function viewmessage($message_id) // no default value means it's required
{
// your code
}
Your controller methods literally accept user input as arguments (whatever's in the address bar). You always have to account for those required arguments not being present in CI controller methods.
function viewmessage($message_id = NULL)
{
if ( ! $message_id) show_404();
// your code
}
This will silence the errors and show a 404 if the required $message_id is not there. Additionally, $this->uri->segment(3) is unnecessary because it should have the same value as $message_id.
I highly discourage redirecting to an error page when you really want a 404, but that's up to you. It sure doesn't help the user realize their mistake when the address is lost after the redirect, and you're sending the wrong HTTP headers by doing so.