What is the table like in which your query inserts data?
And what is the query like? 
And have you read the following page?

http://www.php.net/manual/function.mysql-insert-id.php

--Jani

mysql> show columns from staff; 
+-----------+--------------+------+-----+---------+----------------+
| Field     | Type         | Null | Key | Default | Extra          |
+-----------+--------------+------+-----+---------+----------------+
| id        | int(11)      |      | PRI | NULL    | auto_increment |
| firstname | varchar(80)  | YES  |     | NULL    |                |
| lastname  | varchar(80)  | YES  |     | NULL    |                |
| title     | varchar(80)  | YES  |     | NULL    |                |
| phone     | varchar(15)  | YES  |     | NULL    |                |
| cell      | varchar(15)  | YES  |     | NULL    |                |
| home      | varchar(15)  | YES  |     | NULL    |                |
| pager     | varchar(60)  | YES  |     | NULL    |                |
| email     | varchar(30)  | YES  |     | NULL    |                |
| username  | varchar(16)  | YES  |     | NULL    |                |
| password  | varchar(16)  | YES  |     | NULL    |                |
| epassword | varchar(16)  | YES  |     | NULL    |                |
| company   | int(11)      | YES  |     | NULL    |                |
| role      | varchar(80)  | YES  |     | NULL    |                |
| other     | varchar(15)  | YES  |     | NULL    |                |
| active    | tinyint(4)   | YES  |     | NULL    |                |
| shell     | varchar(128) | YES  |     | NULL    |                |
| forward   | varchar(64)  | YES  |     | NULL    |                |
| disporder | int(11)      | YES  |     | NULL    |                |
+-----------+--------------+------+-----+---------+----------------+

 $query="insert into staff (id, firstname, lastname, title, phone, cell, home, pager, email, username, password, epassword, company, role, other, active, shell, forward, disporder) values (NULL, '$this->firstname', '$this->lastname', '$this->title', '$this->phone', '$this->cell', '$this->home', '$this->pager', '$this->email', '$this->username', '$this->password', '$this->epassword', '$this->company', '$this->role', '$this->other', '1', '$this->shell', '', $this->disporder)";
 $cursor=mysql_db_query('staff', $query, $connection);
                // Need to check return here.
                $this->id=mysql_insert_id($connection);
echo  "Connection: $connection<br>\nID: $this->id<br>\n";

When run $connection is set to a valid resource and $this->id is 0.

The data does get inserted into the database without any problems so I know the query is good.

I looked at the page referenced and the auto_increment field is a standard int field.   The LAST_INSERT_ID() function appears to work but am curious as to why the mysql_insert_id does not.

Why do you have the 'id' in your SQL line? You don't need to mention
it at all, it's 'auto_increment'. ie. it will be automatically incremented.

Try leaving it out. mysql_insert_id() should work then.


--Jani

No feedback and an user error.

--Jani