fixed "not working" save in Calendar >> Site config, gave a wrong, but not displayed, validation error

calendar/inc/class.calendar_hooks.inc.php

@@ -728,9 +728,9 @@ function calendar_purge_old($config)
 			'calendar.calendar_boupdate.purge',
 			(float)$config
 		);
-	}
-	if(!$result)
-	{
-		$GLOBALS['config_error'] = 'Unable to schedule purge';
+		if(!$result)
+		{
+			$GLOBALS['config_error'] = 'Unable to schedule purge';
+		}
 	}
 }

calendar/templates/default/config.tpl

@@ -1,5 +1,7 @@
 <!-- BEGIN header -->
+<p style="text-align: center; color: red; font-weight: bold;">{error}</p>
 <form method="POST" action="{action_url}">
+{hidden_vars}
 <table border="0" align="center">
    <tr class="th">
     <td colspan="2"><font color="{th_text}">&nbsp;<b>{title}</b></font></td>