使用require（）不会加载php文件

//index.php

    if(isset($_GET["action"])){
        if($_GET["action"]=="add_admin"){
            require("../gbl_admin/admin_header.php");
            require("../gbl_admin/admin_add.php");
        }
    }

//admin_header.php

    require("../gbl_admin/db/db_ini.php");
    require("../gbl_admin/classes/dbmgmt.php");
    require("../gbl_admin/configuration/passwordhash.php");

I have created a in dbmgmt to handle database but after calling it through index.php and submitting the form it gives me "Creating default object from empty value " error as well as "Call to undefined function create_hash()" error from passwordhash.php file. This means that the files are not being loaded by index.php. How do i fix this??

I would suggest you always use absolute paths by using __DIR__, or for less than PHP 5.3, use dirname(__FILE__)

This will mean that your include should be along the lines of

require(__DIR__."/../gbl_admin/admin_header.php");

However, as you are using require, and you are saying the files are not being required, the only logical explanation is that your if condition is not being satisfied.

Try:

if(isset($_GET["action"])){
        if($_GET["action"]=="add_admin"){
            require("../gbl_admin/admin_header.php");
            require("../gbl_admin/admin_add.php");
        }else{
           die('error 1');
        }
}else{
    die('error 2');
}