EWSEL on "Getting Member Function Error"

Hallo,

i made a custom post loop query to load a meta data.
I get this error:
Fatal error: Call to a member function have_posts() on a non-object in /home/usr/public_html/wp-content/themes/skin/tabs/lib/link_tab.php on line 98

Code from link_tab.php line 98-104

while ( $linktab->have_posts() ) : $linktab->the_post();
$custom_fields = get_post_custom();
global $post;
$link_tab = get_post_meta($post->ID,'link_tab', true );
foreach ( $link_tab as $key => $value ) {
require_once ('linksload.php'); //php code file
$link = new Link( $value );
?>

i can not see any error its work perfekt if i use the $value as url