diff --git a/erpnext/stock/utils.py b/erpnext/stock/utils.py
index 0d95c58..3f9de86 100644
--- a/erpnext/stock/utils.py
+++ b/erpnext/stock/utils.py
@@ -92,6 +92,9 @@
 def get_incoming_rate(args):
 	"""Get Incoming Rate based on valuation method"""
 	from erpnext.stock.stock_ledger import get_previous_sle
+	
+	if isinstance(args, basestring):
+		args = json.loads(args)
 
 	in_rate = 0
 	if (args.get("serial_no") or "").strip():