y en ese mismo script ejecutas
var_dump() sobre las variables de conexión??
Edito: rápidamente revise el manual de PHP y mira lo que nos dice:
Cita: If a second call is made to mysql_connect() with the same arguments, no new link will be established, but instead, the link identifier of the already opened link will be returned. The new_link parameter modifies this behavior and makes mysql_connect() always open a new link, even if mysql_connect() was called before with the same parameters. In SQL safe mode, this parameter is ignored.
http://php.net/mysql_connect