You shouldn't print the Content-Type header if you are going to redirect. It should be one or the other, so:

use CGI qw( :standard );
use CGI::Carp qw( fatalsToBrowser );

print redirect("/login.html") and exit 0 unless defined param("Name");

my $Name = param("Name");
my $Password = param("Password");
print header;   # CGI.pm method
# print "Content-type: text/html\n\n";
[download]

The logic could as easily be done in an if(){}else{} type construct, but I like the directness of this way. I omitted definedness checking on param('Password'), but you might want to add it in.

Update: You also need to print the redirect, corrected in code.

After Compline,
Zaxo