PHP List Users Page w/ Extra Fields plugin

I’m having a issue getting a php function to pull user info entered using the Extra Fields plugin.

Here’s the code:

<?php
$szSort = "user_login";
$aUsersID = $wpdb->get_col( $wpdb->prepare("SELECT $wpdb->users.ID FROM $wpdb->users ORDER BY $szSort"));
foreach ( $aUsersID as $iUserID ) :
$user = get_userdata( $iUserID );
echo("<tr><td>" . $user->last_name . "</td><td>" . $user->first_name . "</td><td>" . $user->wpum_phonenumber . "</td><td>" . $user->wpum_city .  "</td><td>" . $user->wpum_state  .  "</tr>");
endforeach; // end the users loop.
?>

I’m using this to create a membership list on one of the pages, but I can’t get it to pull anything starting with “wpum_”. I have a very basic working knowledge of php so I imagine the issue is right in front of me, but I need a fresh set of eyes to take a look.