How to enable template awareness in Get Author Profile plugin?

As I mentioned here, this code isn’t working for me consistently. As did the original author of the referenced thread, I want to have the author’s name in a heading that comes before the execution of The Loop in an author template. At first I tried it this way:
<?php
if(get_query_var('author_name')) :
$curauth = get_userdatabylogin(get_query_var('author_name'));
else :
$curauth = get_userdata(get_query_var('author'));
endif;
?>
<h3>These are excerpts of all of <?php echo $curauth->user_nickname; ?>'s entries. Click on the title of each entry to view the full post.</h3>
but only two of my nine authors’ names showed up that way. Why should that be? They all have nicknames.

So then I remembered that Kafkaesqui, the author of the Get Author Profile plugin, said in his latest update that he made the plugin “template aware.” I thought that meant I could use his plugin template tag before The Loop in an author template and WordPress would already know which author to use. So I changed the previous code to
<h3>These are excerpts of all of <?php get_author_profile('nickname'); ?>'s entries. Click on the title of each entry to view the full post.</h3>
and now none of the authors’ names show up in this heading. What am I doing wrong?