never mind, I got it.
and for anyone else who wants this:
delete this code:
function show_author_select() {
global $wpdb, $tableusers, $author;
$users = $wpdb->get_results("SELECT * FROM $tableusers WHERE user_level > 0", ARRAY_A);
$output .= '<option value="">All Authors</option>'.NL;
foreach ($users as $user) {
$output .= '<option value="'.$user['ID'].'"';
if ($user['ID'] == $author) {
$output .= 'selected="selected"';
}
$output .= '>'.$user['user_nickname'].'</option>'.NL;
}
$output = '<select name="author">'.NL.$output.'</select>'.NL;
echo $output;
}
and this line:
`<?php show_author_select() ?>1