well in order to do changes to the site you will have to gain the username and password to that site if ur site is uploaded to a ftp then find out the ftp info by goign to the main schools web designers pc and install a keylogger onto there pc. then u can get information and then logon to the ftp and upload your own new defaced website page.
as for the serial key i really dont remember where i got it lol im sry
glad u like it to
as for the error that means the site was temporarily down due to u.
i hope that you used a proxy of some sort to hide your ip.