On Clic Install

Hi,
here my considerations in order to WP “OneClicInstall”:

1 create a php page containing a form asking: blog name, user name, user email, blog content.

2 on form submit I record the data of step 1 on a database for administrative uses; I write also a ‘onfly’ WP user password and the other data: DB_NAME, DB_HOST, DB_USER, DB_PASSWORD, eccetera

3 A query extract user data and write wp-config.php.

4 Create an empty database with database name = user name; create database user + password created onfly.

5 Ready to standard install.

Well, now, instead of activate step 5, I try to launch the following url:

http://localhost/myblog/wp-admin/install.php?step=2&weblog_title=myblog&user_name=admin&admin_password=mypassword&admin_password2=mypassword&admin_email=myemail%40mydomain.com&blog_public=1&Submit=Install+WordPress

The browser answer is: invalid email.
Change myemail%40mydomain.com with [email protected]
but with any results.

Were is the problem ?
Bye