Errors when trying to integrate Wordpress on my existing website

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I followed this guide from Wordpress Codex: <a href="http://codex.wordpress.org/Integrating_WordPress_with_Your_Website" rel="nofollow">Integrating Wordpress with Your Website</a>
but I'm getting the following errors:

Declaration of Walker_Page::start_lvl() should be compatible with that of Walker::start_lvl() [ On E:\Documents\work\devenv\xampp\htdocs\orp\blog\wp-includes\post-template.php Line 1071 ]
Declaration of Walker_Page::end_lvl() should be compatible with that of Walker::end_lvl() [ On E:\Documents\work\devenv\xampp\htdocs\orp\blog\wp-includes\post-template.php Line 1071 ]
Declaration of Walker_Page::start_el() should be compatible with that of Walker::start_el() [ On E:\Documents\work\devenv\xampp\htdocs\orp\blog\wp-includes\post-template.php Line 1071 ]
Declaration of Walker_Page::end_el() should be compatible with that of Walker::end_el() [ On E:\Documents\work\devenv\xampp\htdocs\orp\blog\wp-includes\post-template.php Line 1071 ]
Declaration of Walker_PageDropdown::start_el() should be compatible with that of Walker::start_el() [ On E:\Documents\work\devenv\xampp\htdocs\orp\blog\wp-includes\post-template.php Line 1116 ]
Declaration of Walker_Category::start_lvl() should be compatible with that of Walker::start_lvl() [ On E:\Documents\work\devenv\xampp\htdocs\orp\blog\wp-includes\category-template.php Line 915 ]
Declaration of Walker_Category::end_lvl() should be compatible with that of Walker::end_lvl() [ On E:\Documents\work\devenv\xampp\htdocs\orp\blog\wp-includes\category-template.php Line 915 ]
Declaration of Walker_Category::start_el() should be compatible with that of Walker::start_el() [ On E:\Documents\work\devenv\xampp\htdocs\orp\blog\wp-includes\category-template.php Line 915 ]
Declaration of Walker_Category::end_el() should be compatible with that of Walker::end_el() [ On E:\Documents\work\devenv\xampp\htdocs\orp\blog\wp-includes\category-template.php Line 915 ]
Declaration of Walker_CategoryDropdown::start_el() should be compatible with that of Walker::start_el() [ On E:\Documents\work\devenv\xampp\htdocs\orp\blog\wp-includes\category-template.php Line 966 ]
Declaration of Walker_Comment::start_lvl() should be compatible with that of Walker::start_lvl() [ On E:\Documents\work\devenv\xampp\htdocs\orp\blog\wp-includes\comment-template.php Line 1400 ]
Declaration of Walker_Comment::end_lvl() should be compatible with that of Walker::end_lvl() [ On E:\Documents\work\devenv\xampp\htdocs\orp\blog\wp-includes\comment-template.php Line 1400 ]
Declaration of Walker_Comment::start_el() should be compatible with that of Walker::start_el() [ On E:\Documents\work\devenv\xampp\htdocs\orp\blog\wp-includes\comment-template.php Line 1400 ]
Declaration of Walker_Comment::end_el() should be compatible with that of Walker::end_el() [ On E:\Documents\work\devenv\xampp\htdocs\orp\blog\wp-includes\comment-template.php Line 1400 ]
Redefining already defined constructor for class WP_Widget [ On E:\Documents\work\devenv\xampp\htdocs\orp\blog\wp-includes\widgets.php Line 93 ]
Declaration of Walker_Nav_Menu::start_lvl() should be compatible with that of Walker::start_lvl() [ On E:\Documents\work\devenv\xampp\htdocs\orp\blog\wp-includes\nav-menu-template.php Line 109 ]
Declaration of Walker_Nav_Menu::end_lvl() should be compatible with that of Walker::end_lvl() [ On E:\Documents\work\devenv\xampp\htdocs\orp\blog\wp-includes\nav-menu-template.php Line 109 ]
Declaration of Walker_Nav_Menu::start_el() should be compatible with that of Walker::start_el() [ On E:\Documents\work\devenv\xampp\htdocs\orp\blog\wp-includes\nav-menu-template.php Line 109 ]
Declaration of Walker_Nav_Menu::end_el() should be compatible with that of Walker::end_el() [ On E:\Documents\work\devenv\xampp\htdocs\orp\blog\wp-includes\nav-menu-template.php Line 109 ]
Fatal error: Call to a member function add_rewrite_tag() on a non-object in E:\Documents\work\devenv\xampp\htdocs\orp\blog\wp-includes\taxonomy.php on line 333

Quite a mouthfull of errors! I'm on Wordpress v3.3.1 and PHP v5.3.1
My php.ini error reporting is

error_reporting = E_ALL & ~E_NOTICE & ~E_STRICT

, but not sure if error_reporting is getting override somewhere in the code.

I poked around the Wordpress php files and saw the function arguments mismatching issue in

wp-includes/class-wp-walker.php

, but I don't want to just hotfix it by matching the arguments, without knowing the real issue.

Do you have any clue what might be going on here?

Thanks a lot!

<strong>EDIT:</strong> Fixed all the Declaration errors, now just one remains

Fatal error: Call to a member function add_rewrite_tag() on a non-object in E:\Documents\work\devenv\xampp\htdocs\orp\blog\wp-includes\taxonomy.php on line 334

It seems

$wp_rewrite

is not getting defined and its value is <em>null</em>. In fact all global variables are not availble inside

wp-includes\taxonomy.php