Component install error: JInstaller: :Install: File does not exist



PHP Snippet 1:

<languages>
        <language tag="en-GB" client="site">language/en-GB/en-GB.com_helloworld.ini</language>
        <language tag="en-GB" client="site">language/en-GB/en-GB.com_helloworldt.sys.ini</language>
</languages>

PHP Snippet 2:

<administration>
... 
    <languages>
            <language tag="en-GB" client="site">language/en-GB/en-GB.com_helloworld.ini</language>
            <language tag="en-GB" client="site">language/en-GB/en-GB.com_helloworld.sys.ini</language>
    </languages>
...
</administration>

PHP Snippet 3:

<?xml version="1.0" encoding="utf-8"?>

PHP Snippet 4:

<name>com_helloworld</name>
<creationDate>November 2009</creationDate>
<author>David Thorn</author>
<authorEmail>[email protected]</authorEmail>
<authorUrl>http://www.example.org</authorUrl>
<copyright>Copyright Info</copyright>
<license>License Info</license>
<version>1.0.0.1</version>
<description>Description of the Hello World component ...</description>
<files folder="site">
        <filename>index.html</filename>
        <filename>helloworld.php</filename>
        <filename>controller.php</filename>
        <folder>css</folder>
        <folder>js</folder>
        <folder>views</folder>
        <folder>models</folder>
        <folder>controllers</folder>
        <folder>helpers</folder>
        <folder>language</folder>
    </files>
    <languages folder="site">
                    <language tag="en-GB">language/en-GB/en-GB.com_helloworld.ini</language>
                    <language tag="en-GB">language/en-GB/en-GB.com_helloworld.sys.ini</language>
    </languages>    
<administration>
        <menu>com_helloworld</menu>
        <files folder="admin">
            <filename>index.html</filename>
            <filename>helloworld.php</filename>
            <filename>controller.php</filename>
            <folder>css</folder>
            <folder>js</folder>
            <folder>views</folder>
            <folder>models</folder>
            <folder>controllers</folder>
            <folder>helpers</folder>
            <folder>language</folder>
        </files>
        <languages folder="admin">
                    <language tag="en-GB">language/en-GB/en-GB.com_helloworld.ini</language>
                    <language tag="en-GB">language/en-GB/en-GB.com_helloworld.sys.ini</language>
        </languages>            
</administration>

PHP Snippet 5:

jimport('joomla.application.component.controller');

PHP Snippet 6:

defined('_JEXEC') or die('Restricted access');

PHP Snippet 7:

$controller = JController::getInstance('Helloworld');

PHP Snippet 8:

$controller = JControllerLegacy::getInstance('Helloworld');