diff --git a/check_apaches.py b/check_apaches.py
index 9c27875..46d4adf 100755
--- a/check_apaches.py
+++ b/check_apaches.py
@@ -78,13 +78,20 @@ class CheckApaches(MonitoringPlugin):
 			returncode = self.value_wc_to_returncode(self.apache_busy, warn, crit)
 			output = '%d busy workers' % self.apache_busy
 			pd['value'] = self.apache_busy
+			pd = [pd]
 		elif target == 'idle':
 			returncode = self.value_wc_to_returncode(self.apache_idle, warn, crit)
 			output = '%d idle workers' % self.apache_idle
 			pd['value'] = self.apache_idle
 			pd['label'] = 'worker_idle'
+			pd = [pd]
+		else:
+			returncode = 3
+			output = 'Target "%s" unknown' % target
+			pd = None
 
-		return self.remember_check('worker', returncode, output, perfdata=[pd], target=target)
+
+		return self.remember_check('worker', returncode, output, perfdata=pd, target=target)
 
 
 	def get_server_status(self):