PHP/MySQL guestlist help

foges

I hope this fits in here,
Ok, im creating a guest list for a party and because im not too proficient in php and im lazy i decided id try and find a premade script and i found this one:

http://homework.nwsnet.de/products/11

Firstly i uploaded all the files and CHMOD'd all the files to 777 (i know they probably dont need it but at least that wont be my problem)

I also edited the mod.guests.php and changed the:

mysql info to

var $db_host = "localhost";
var $db_user = "colourof_grad";
var $db_pass = "mypassword";
var $db_name = "colourof_grad";
var $db_tbl = "guests";

At my website I created a new mysql database (grad, which is called colourof_grad). I created a new username and password (grad, which is also called colourof_grad). Then i added the username to the database. In phpmyadmin i imported the .sql file, which created a table called guests.

When i then navigate to the mod.guests.php file i get an "Internal Server Error"

The error_log says "PHP Warning: mysql_select_db(): supplied argument is not a valid MySQL-Link resource in /home/colourof/public_html/grad/mod.guests.php on line 66"

Any ideas what i could be doing wrong. or any ideas where i could find a simple guest list script. I just need something with imput fields of "your name" and "guests name". They should then be organised so the people you add are listed under you name.

Thanx a lot for the help :D