Files not found while installing magento 1.9

[mohamednagy]

I'm trying to install magento 1.x on my centos machine. After dowloading and extracting magento i faced this errrors.

Warning: include_once(Mage/Core/functions.php): failed to open stream: No such file or directory in /home/xxxx/app/Mage.php on line 50

Warning: include_once(): Failed opening 'Mage/Core/functions.php' for inclusion (include_path='.:/usr/lib/php:/usr/local/lib/php:/home/username/php') in /home/xxxx/app/Mage.php on line 50

Warning: include_once(Varien/Autoload.php): failed to open stream: No such file or directory in /home/xxxx/app/Mage.php on line 51

Warning: include_once(): Failed opening 'Varien/Autoload.php' for inclusion (include_path='.:/usr/lib/php:/usr/local/lib/php:/home/username/php') in /home/xxxx/app/Mage.php on line 51

Fatal error: Class 'Varien_Autoload' not found in /xxxx/app/Mage.php on line 54

I tried to run

php shell/compiler.php compile

 the the errors disappeared and the installation page appeared but without any next or back buttons. How can i fix this issue?

[SindreM]

Looks like the include paths are not being set correctly. Magento adds additional folders to the include path variable, which tells PHP where to look for file includes, e.g. ./app/code/core/.  The include path is set in the app/Mage.php file as part of the bootstrap procedure:

define('DS', DIRECTORY_SEPARATOR);
define('PS', PATH_SEPARATOR);
define('BP', dirname(dirname(__FILE__)));

Mage::register('original_include_path', get_include_path());

if (defined('COMPILER_INCLUDE_PATH')) {
    $appPath = COMPILER_INCLUDE_PATH;
    set_include_path($appPath . PS . Mage::registry('original_include_path'));
    include_once "Mage_Core_functions.php";
    include_once "Varien_Autoload.php";
} else {
    /**
     * Set include path
     */
    $paths[] = BP . DS . 'app' . DS . 'code' . DS . 'local';
    $paths[] = BP . DS . 'app' . DS . 'code' . DS . 'community';
    $paths[] = BP . DS . 'app' . DS . 'code' . DS . 'core';
    $paths[] = BP . DS . 'lib';

    $appPath = implode(PS, $paths);
    set_include_path($appPath . PS . Mage::registry('original_include_path'));
    include_once "Mage/Core/functions.php";
    include_once "Varien/Autoload.php";

Make sure that the set_include_path function is not disabled by php.ini. You can also add some debug code after the call to set_include_path in the file above to retrieve the current value of include_path, like this:

echo "Include path: " . get_include_path();

[mohamednagy]

Thank you for your reply.

I tried to debug set_inlcude_path in app/Mage.php but magento tries to set value

 set_include_path($appPath . PS . Mage::registry('original_include_path'));
 echo $appPath . PS . Mage::registry('original_include_path');
 //output: /home/****/app/code/local:/home/****/app/code/community:/home/****/app/code/core:/home/****/lib:.:/usr/lib/php:/usr/local/lib/php:/home/username/phpInclude 

and when i print the value 

echo "Include path: " . get_include_path();
//output: .:/usr/lib/php:/usr/local/lib/php:/home/username/php

set_include_path is always returning false.

How can i check if set_include_path is enabled or disabled?