Q:

hello world in magento not working

I just want to create a separate module for my magento website.I just follow the same steps as mentioned here. But I am getting 404 error.
I dont know why it's happening.I am having my default store view in admin panel. Is that any reason it's not working ???
This is the url I am currently running to print "Hello index"
http://my_domain.ca/web/frontier/helloworld 
Please help me guys if you can. I am asking here on stackoverflow because that blog is 3 years old and I will not get reply from there soon so.
config.xml
<config>    
    <modules>
        <Alanstormdotcom_Helloworld>
            <version>0.1.0</version>
        </Alanstormdotcom_Helloworld>
    </modules>
</config> 

<config>    
    <frontend>
        <routers>
            <helloworld>
                <use>standard</use>
                <args>
                    <module>Alanstormdotcom_Helloworld</module>
                    <frontName>helloworld</frontName>
                </args>
            </helloworld>
        </routers>  
    </frontend>
</config> 

and Alanstormdotcom_Helloworld.xml
<config>
    <modules>
        <Alanstormdotcom_Helloworld>
            <active>true</active>
            <codePool>local</codePool>
        </Alanstormdotcom_Helloworld>
    </modules>
</config>

A:

You have used <.config> twice in your config.xml file and it causes error. Your config file should be like this.
<config>    
<modules>
    <Alanstormdotcom_Helloworld>
        <version>0.1.0</version>
    </Alanstormdotcom_Helloworld>
</modules>   
<frontend>
    <routers>
        <helloworld>
            <use>standard</use>
            <args>
                <module>Alanstormdotcom_Helloworld</module>
                <frontName>helloworld</frontName>
            </args>
        </helloworld>
    </routers>  
</frontend>
</config> 

This file should be in the location app/code/local/Alanstormdotcom/Helloworld/etc/config.xml. 
You need to add controller file also. It should add in the location app/code/local/Alanstormdotcom/Helloworld/controllers/IndexController.php
<?php

class Myproject_Helloworld_IndexController extends Mage_Core_Controller_Front_Action
{
   public function indexAction()
  {
      echo 'Hello world!';
  }
}

Note the names of each folder. The first letter should be capital. In controller file, you can see that, i didnt use ?> symbol. This is because it is the covention that we are using in magento files. 
Now clear cache. and try to load the page. Page url should be 
yourdomain.com/index.php/hellworld

