diff --git a/Makefile b/Makefile
index 4a90a27f068592e13147714a21305ffff39de178..41f47779baf36e2d48f6fcf13e5b0942b7b6640f 100644
--- a/Makefile
+++ b/Makefile
@@ -2,7 +2,7 @@ BASE=rules_shipping
 BASE_ADV=rules_shipping_advanced
 PLUGINTYPE=vmshipment
 ZIPBASE=opentools_vm
-VERSION=5.0
+VERSION=5.1
 
 PLUGINFILES=$(BASE).php $(BASE)_base.php $(BASE).script.php $(BASE).xml index.html
 PLUGINFILES_ADV=$(BASE_ADV).php $(BASE)_base.php $(BASE_ADV).script.php $(BASE_ADV).xml index.html
diff --git a/releases/plg_opentools_vm_rules_shipping_advanced_v5.1.zip b/releases/plg_opentools_vm_rules_shipping_advanced_v5.1.zip
new file mode 100644
index 0000000000000000000000000000000000000000..ea490db0bb9429e23984c79bc1cf6203a500b603
Binary files /dev/null and b/releases/plg_opentools_vm_rules_shipping_advanced_v5.1.zip differ
diff --git a/releases/plg_opentools_vm_rules_shipping_v5.1.zip b/releases/plg_opentools_vm_rules_shipping_v5.1.zip
new file mode 100644
index 0000000000000000000000000000000000000000..bf6e7dedece2f2eb4083137831a84313907d8c53
Binary files /dev/null and b/releases/plg_opentools_vm_rules_shipping_v5.1.zip differ
diff --git a/rules_shipping.xml b/rules_shipping.xml
index f7e00d0c61839dade50150c0dd50027ed8ee1003..524caace49178196fa2fd7b62049958d25b57523 100644
--- a/rules_shipping.xml
+++ b/rules_shipping.xml
@@ -6,7 +6,7 @@
     <authorUrl>http://www.open-tools.net</authorUrl>
     <copyright>Copyright (C) 2013-2014, Reinhold Kainhofer</copyright>
     <license>GPL v3+</license>
-    <version>5.0</version>
+    <version>5.1</version>
     <description>VMSHIPMENT_RULES_DESC</description>
     <files>
         <filename plugin="rules_shipping">rules_shipping.php</filename>
diff --git a/rules_shipping_advanced.php b/rules_shipping_advanced.php
index a8487a6ed32cb44eee57e29d572e52a63074435b..334ca0b1665c587b0cfafc8190ee6137712a32d3 100644
--- a/rules_shipping_advanced.php
+++ b/rules_shipping_advanced.php
@@ -148,7 +148,7 @@ class ShippingRule_Advanced extends ShippingRule {
 		/* In the advanced version, all conditions and costs can be given as a full mathematical expression */
 		/* Both versions create an expression tree, which can be easily evaluated in evaluateTerm */
 		$rulepart = trim($rulepart);
-		if (empty($rulepart)) return;
+		if (!isset($rulepart) || $rulepart==='') return;
 
 		
 		// Special-case the name assignment, where we don't want to interpret the value as an arithmetic expression!
@@ -410,7 +410,7 @@ class ShippingRule_Advanced extends ShippingRule {
 			$this->ruletype = 'shipping';
 			$this->includes_tax = False;
 		}
-// 		JFactory::getApplication()->enqueueMessage("<pre>Rule part '$rulepart' parsed into (condition=".print_r($is_condition,1).", assignment=".print_r($is_assignment,1)."): ".print_r($res,1)."</pre>", 'error');
+// 		JFactory::getApplication()->enqueueMessage("<pre>Rule part '$rulepart' (type $this->ruletype) parsed into (condition=".print_r($is_condition,1).", assignment=".print_r($is_assignment,1)."): ".print_r($res,1)."</pre>", 'error');
 	}
 
 
diff --git a/rules_shipping_advanced.xml b/rules_shipping_advanced.xml
index 99d76bb09e88b98970a8dfcd08b3283f73433f98..17196c9dbec0a61a0457a9cb53495fb297c8ca3d 100644
--- a/rules_shipping_advanced.xml
+++ b/rules_shipping_advanced.xml
@@ -6,7 +6,7 @@
     <authorUrl>http://www.open-tools.net</authorUrl>
     <copyright>Copyright (C) 2013-2014, Reinhold Kainhofer</copyright>
     <license>GPL v3+</license>
-    <version>5.0</version>
+    <version>5.1</version>
     <description>VMSHIPMENT_RULES_ADV_DESC</description>
     <files>
         <filename plugin="rules_shipping_advanced">rules_shipping_advanced.php</filename>