Warning: mysql_connect(): mysqlnd cannot connect to MySQL 4.1+ using the old ...
有些程序在安装时，出现如下错误：
Warning: mysql_connect(): mysqlnd cannot connect to MySQL 4.1+ using the old insecure authentication. Please use an administration tool to reset your password with the command SET PASSWORD = PASSWORD('your_existing_password'). This will store a new, and more secure, hash value in mysql.user. If this user is used in other scripts executed by PHP 5.2 or earlier you might need to remove the old-passwords flag from your my.cnf file in K:\WEB_2013\www.aerchi.com\***\***.php
这个问题主要就是因为数据库的登陆密码编码问题，将密码设置成41位，即可。
进入phpmyadmin,点击SQL。输入以下两条命令，然后执行即可。
SET SESSION old_passwords = FALSE;SET PASSWORD = PASSWORD('your password');
