Use the built in sucs-site error handling stuff.

components/susignup-admin.php

@@ -38,16 +38,19 @@ if (isset($session->groups[$permission])) {
                 $smarty->assign("error_text", "Search term doesn't look like a valid student ID");
             } else {
                 // they have given us a valid sid lets check to see if they have paid
+                $sid = $_REQUEST['sid'];
 
                 // make sure the user/admin/exec isn't an idiot
                 // check if they are already signed up and tell them so
                 $tmpresult = $sucsDB->Execute("SELECT * FROM members WHERE sid=?", array($_REQUEST['sid']));
                 if ($tmpresult->fields["sid"] == $sid && $tmpresult->fields["paid"] == paidUntil(time())) {
                     // let them know they are already signed up and renewed
+                    $mode = 'error';
                     message_flash("You are a numpty and have already signed up and paid for this year.");
                     // else if check to see if they have signedup and paid for the new year but haven't renewed
                 } else if ($tmpresult->fields["sid"] == $sid && $tmpresult->fields["paid"] != paidUntil(time())) {
                     // renew them!
+                    $mode = 'error';
                     renew_membership($tmpresult->fields["username"]);
                     // let them know that their account has been renewed
                     message_flash("Your SUCS account has been renewed.");

templates/susignup-admin.tpl

 {if $staff == TRUE}
- {if $mode == 'error'}
+ {*{if $mode == 'error'}
 	<div class='errorbar'>
 		<strong>Error: </strong> {$error_text}
 	</div>
- {/if}
+ {/if}*}
  {if $mode == 'renewals'}
 <form action='{$componentpath}' method='post'>
  <table id='susignup-renewals'>