diff --git a/erpnext/patches/jan_mar_2012/reload_mapper.py b/erpnext/patches/jan_mar_2012/reload_mapper.py
index 3a43d871b9..a6e3102bba 100644
--- a/erpnext/patches/jan_mar_2012/reload_mapper.py
+++ b/erpnext/patches/jan_mar_2012/reload_mapper.py
@@ -5,3 +5,5 @@ def execute():
 	reload_doc('stock', 'DocType Mapper', 'Sales Order-Delivery Note')
 	reload_doc('accounts', 'DocType Mapper', 'Sales Order-Receivable Voucher')
 	reload_doc('accounts', 'DocType Mapper', 'Delivery Note-Receivable Voucher')
+
+	webnotes.conn.sql("delete from `tabField Mapper Detail` where parent = 'Sales Order-Delivery Note' and from_field = 'basic_rate' and to_field = 'basic_rate'")