我得到这个错误尝试访问我们的SCADA网站：

A Database Error Occurred

Unable to connect to your database server using the provided settings.

Filename: core/Loader.php

Line Number: 341

我扫描了Loader.php文件，在第341行发现了以下代码：$CI->db =& DB($params, $active_record);
这是包含错误代码的完整块：

public function database($params = '', $return = FALSE, $active_record = NULL)
    {
        // Grab the super object
        $CI =& get_instance();

        // Do we even need to load the database class?
        if (class_exists('CI_DB') AND $return == FALSE AND $active_record == NULL AND isset($CI->db) AND is_object($CI->db))
        {
            return FALSE;
        }

        require_once(BASEPATH.'database/DB.php');

        if ($return === TRUE)
        {
            return DB($params, $active_record);
        }

        // Initialize the db variable.  Needed to prevent
        // reference errors with some configurations
        $CI->db = '';

        // Load the DB class
        $CI->db =& DB($params, $active_record);
    }