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Change your query_posts call to include global $query_string variable.

Your query_posts should look like following:

<?php 
global $query_string;
query_posts( $query_string . 'cat=".$cat ); 
?>

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)