Index: /mods/wpsg_mod_rechnungen.class.php
===================================================================
--- /mods/wpsg_mod_rechnungen.class.php	(revision 8053)
+++ /mods/wpsg_mod_rechnungen.class.php	(revision 8055)
@@ -1663,5 +1663,5 @@
 			$invoice_data = json_decode($oOrderProduct->getMeta('wpsg_mod_rechnungen_data', false, 'null'), true);
 			
-			foreach ($invoice_data as $id) {
+			foreach (array($invoice_data) as $id) {
 					
 				try {