Do something with $username and $admin.

Perl is warning you that you don't appear to be using those values, and that because of that something might be wrong.

Read perldoc -f our , perldoc vars and perldoc -f my to decide which one you need.

Note that the vars documentation has this note:

NOTE: The functionality provided by this pragma has been superseded by "our" declarations

Update: I think I missed the obvious. Shouldn't it read as follows?

$username = $common::auth::user;
$admin  =  $common::auth::admin;
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package Foo;

# Warning. Rubbish, untested code follows.

sub get_admin {
 my $admin = "admin";
 my $user = $ENV{"REMOTE_USER"};

 return ($admin, $user);
}

package Bar;

use Foo;

@user_info = get_admin();

# Do stuff.
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