How to link avatar and nickname to profile

Question

On the single post page I want to link the avatar function to the author profile, but I tried

<a href="<?php the_author_posts_link(); ?>">
<img src="<?php echo get_avatar($post->post_author, '64', $avatar); ?>">
</a>

but that doesn't work.

Also, how can I display the nickname (display name) and still link to the profile the following code gives a strange link and 404s

<a href="<?php echo get_author_posts_url(); ?>"><?php the_author_nickname(); ?></a>

some help would be greatly appreciated. Thanks