I'm still not sure why you are using a hand coded connection file, but your syntax is wrong. The code:
if (mysqli_errno()) {
die('<p>Failed to connect to MySQL: '.mysqli_error().'</p>');
}
should be:
if (mysqli_errno($conn1_i)) {
die('<p>Failed to connect to MySQL: '.mysqli_error($conn1_i).'</p>');
}