INSERT DATA to 2 tables

[Trilogen]

I am trying to insert data to 2 tables, customers and profile. In customers is an incremental primary key and profile has this as foreign key.

My hopeless attempt below yields an error:

Cannot add or update a child row: a foreign key constraint fails

$db="registrant";
$link = mysql_connect("localhost","user","pass");
//$link = mysql_connect("localhost",$_POST['username'],$_POST['password']);
if (! $link)
die("Couldn't connect to MySQL");
mysql_select_db($db , $link) or die("Select Error: ".mysql_error());
$result=mysql_query("INSERT INTO customers (uname, password) VALUES ('$username','$password')") or die("Customers Insert Error: ".mysql_error());
$result2=mysql_query("INSERT INTO profile (membertype, firstName, lastName, siteAddress, location, skills, description, paytype, email, phone, mobilePhone, msn, yahoo, aim, vidconf) VALUES ('$memtype','$firstname','$lastname','$url','$location','$skills','$description','$pay','$email','$phone','$mPhone','$msn','$yahoo','$aim','$vidconf')")or die("Profile Insert Error: ".mysql_error());
mysql_close($link);
print "Record added\n";

Whats the proper way of doing this?

[abc]

Hi

1. Make sure the foreign key is indexed.
2. Make sure the reference key exists.
3. Make sure the reference key is indexed.
4. Make sure the reference key is the same (size) and (data type) as the foreign key.

abc

[Trilogen]

Originally posted by abc

4. Make sure the reference key is the same (size) and (data type) as the foreign key.

abc [/B]

so this:

CREATE TABLE users (
uid int(11) NOT NULL auto_increment,

and this:

CREATE TABLE profile (
uid int(11) NOT NULL,

is wrong?