Magento - How to create new admin page - magento

Question

I'm using Magento 1.9.0.1 and i've created a new extension in which i've added a new tab in the admin panel take a look at the picture.
Here is what i have in my files.
In: /app/code/community/VivasIndustries/SmsNotification/etc/config.xml:
<?xml version="1.0"?>
<config>
<modules>
<VivasIndustries_SmsNotification>
<version>0.1.0</version>
</VivasIndustries_SmsNotification>
</modules>
<global>
<models>
<smsnotification>
<class>VivasIndustries_SmsNotification_Model</class>
</smsnotification>
</models>
<events>
<sales_order_save_after>
<observers>
<vivasindustries_smsnotification>
<class>smsnotification/observer</class>
<method>orderSaved</method>
</vivasindustries_smsnotification>
</observers>
</sales_order_save_after>
</events>
<helpers>
<smsnotification>
<class>VivasIndustries_SmsNotification_Helper</class>
</smsnotification>
<adminhtml>
<rewrite>
<data>VivasIndustries_SmsNotification_Helper_Adminhtml_Data</data>
</rewrite>
</adminhtml>
</helpers>
</global>
<admin>
<routers>
<adminhtml>
<args>
<modules>
<VivasIndustries_SmsNotification before="Mage_Adminhtml">VivasIndustries_SmsNotification_Adminhtml</VivasIndustries_SmsNotification>
</modules>
</args>
</adminhtml>
</routers>
</admin>
</config>
Here is what i have in: /app/code/community/VivasIndustries/SmsNotification/etc/adminhtml.xml:
<?xml version="1.0"?>
<config>
<menu>
<vivassms translate="title" module="smsnotification">
<title>SMS Center</title>
<sort_order>110</sort_order>
<children>
<sendsms translate="title" module="smsnotification">
<title>Send SMS</title>
<action>adminhtml/magesms_sendsms</action>
<sort_order>1</sort_order>
</sendsms>
<settings>
<title>Settings</title>
<action>adminhtml/system_config/edit/section/vivas/</action>
<sort_order>10</sort_order>
</settings>
<about translate="title" module="smsnotification">
<title>About</title>
<action>adminhtml/smsnotification_about</action>
<sort_order>11</sort_order>
</about>
</children>
</vivassms>
</menu>
<acl>
<resources>
<admin>
<children>
<vivassms>
<title>SMS</title>
<children>
<sendsms translate="title" module="smsnotification">
<title>Send SMS</title>
</sendsms>
<settings>
<title>Settings</title>
<children>
<smsprofile translate="title" module="smsnotification">
<title>Edit user account</title>
</smsprofile>
</children>
</settings>
<about translate="title" module="smsnotification">
<title>About</title>
</about>
</children>
</vivassms>
<system>
<children>
<config>
<children>
<vivassms translate="title" module="smsnotification">
<title>Vivas SMS</title>
</vivassms>
</children>
</config>
</children>
</system>
</children>
</admin>
</resources>
</acl>
</config>
I've added these three children tabs to the created new tab SMS Center but when i click on the About tab i got error 404 ON MY FRONTEND. This is awkward. Why i got redirected to the frontend ?
Can you please help me out to create a simple new custom page in the admin panel where i want to add a simple text?
Thanks in advance!

Answer 1

Seems like Magento recognizes your module is telling it "Check me for admin" controllers, but that Magento doesn't find any. The best way to figure out what Magento thinks your controller file should be named (as well as which folder it should be located in) is to add some temporary debugging to _validateControllerClassName
protected function _validateControllerClassName($realModule, $controller)
{
$controllerFileName = $this->getControllerFileName($realModule, $controller);
if (!$this->validateControllerFileName($controllerFileName)) {
var_dump($controllerFileName); //add this line
return false;
}
This will dump out every file Magento checks for a controller. Look for the line with your module name in it, and compare paths between where your file is located and where Magento thinks it should be located.