diff --git a/buying/utils.py b/buying/utils.py
index 9d125de..0431e64 100644
--- a/buying/utils.py
+++ b/buying/utils.py
@@ -53,7 +53,7 @@
 		"qty": 0,
 		"stock_uom": item.stock_uom,
 		"uom": item.stock_uom,
-		"conversion_factor": 1,
+		"conversion_factor": 1.0,
 		"warehouse": args.warehouse or item.default_warehouse,
 		"item_tax_rate": json.dumps(dict(([d.tax_type, d.tax_rate] for d in 
 			item_wrapper.doclist.get({"parentfield": "item_tax"})))),
diff --git a/controllers/buying_controller.py b/controllers/buying_controller.py
index c49bf2a..e5b8b07 100644
--- a/controllers/buying_controller.py
+++ b/controllers/buying_controller.py
@@ -331,7 +331,9 @@
 	# update valuation rate
 	def update_valuation_rate(self, parentfield):
 		for d in self.doclist.get({"parentfield": parentfield}):
-			if d.qty:
+			if d.item_code and d.qty:
+				# if no item code, which is sometimes the case in purchase invoice, 
+				# then it is not possible to track valuation against it
 				d.valuation_rate = (flt(d.purchase_rate or d.rate)
 					+ (flt(d.item_tax_amount) + flt(d.rm_supp_cost)) / flt(d.qty)
 					) / flt(d.conversion_factor)