<div id="post_message_$post[postid]" 
 class="overflow_parent"><div class="overflow_child">$post[message]
 </div></div> and replace it with

<if condition="$show['member']">         
 <div id="post_message_$post[postid]" class="overflow_parent">
 <div class="overflow_child">$post[message]</div></div>
  <else />                           
 <if condition="$post[postcount] == 1">         
 <div id="post_message_$post[postid]" class="overflow_parent">
 <div class="overflow_child">$post[message]</div></div>         
 </if>         <else />         
 <if condition="$show['guest']">         
 <if condition="$post[postcount] != 1">         
 <br><br>Üye olmadan yorumları göremezsini, hemen buradan üye olun<a href=register.php>Please Click Here</a>         
 <br><br>         
 </if></if></if>