Custom meta fields for specific custom type only

EDIT: I also recommand you to use nonces to check your field before saving.

EDIT2: Nonces

Just before field, define a nonce :

wp_nonce_field( 'curiculum_meta_box_nonce', 'meta_box_nonce' );

Your saving function is not correct, use this instead :

  function save_curiculum_date($postid) {
    //stop if autosave
    if( defined( 'DOING_AUTOSAVE' ) && DOING_AUTOSAVE ) return;

    // if our nonce isn't there, or we can't verify it, stop
    if( !isset( $_POST['meta_box_nonce'] ) || !wp_verify_nonce( $_POST['meta_box_nonce'], 'curiculum_meta_box_nonce' ) ) return;

    // if our current user can't edit this post, stop
    if( !current_user_can( 'edit_post' ) ) return;

update_post_meta($postid, "curiculum_date_from", $_POST["curiculum_date_from"]);
}

The fields function is not correct, use this instead :

$curiculum_date_from = get_post_meta(get_the_ID(),'curiculum_date_from',true);
?>
<p>
    <label for="curiculum_date_from">Date:</label><br />
    <input size="32" type="text" name="curiculum_date_from" id="curiculum_date_from" value="<?php echo $curiculum_date_from; ?>" />