OK, i see.
I added the where clause black and added a hidden for element to the search form to retain the client ID value:
<input type="hidden" name="AccountantID" id="AccountantID" value="<?php echo(isset($_GET['AccountantID'])?$_GET['AccountantID']:""); ?>" />
i also updated the reset link so it would retain the AccountID:
href="acclients_results.php?reset=true&AccountantID=<?php echo(isset($_GET['AccountantID'])?$_GET['AccountantID']:""); ?>"