Custom post type archive page for multiple post types

From WordPress Codex:

Function Reference/post type archive title

This is optimized for archive.php and archive-{posttype}.php template
files for displaying the title of the post type.

“Title of post type” is the label, not the post type registered name.

You can get the registered post type name using get_queried_object(); like this:

<?php
 $obj = get_queried_object();
 $post_type = $obj->name;
?>

I see in your $args array, the caller_get_posts, if you are using WordPress 3.1+, i suggest you to use ignore_sticky_posts that replaced the previous one. Look this ( pagination parameters ).

Maybe i’m wrong maybe not, if you have any problems, reply here : )