[fix] the case when party account currency is missing
diff --git a/erpnext/controllers/accounts_controller.py b/erpnext/controllers/accounts_controller.py
index a92d070..daf3377 100644
--- a/erpnext/controllers/accounts_controller.py
+++ b/erpnext/controllers/accounts_controller.py
@@ -428,7 +428,10 @@
 			if party_type and party:
 				party_account_currency = get_party_account_currency(party_type, party, self.company)
 
-				if party_account_currency != self.company_currency and self.currency != party_account_currency:
+				if (party_account_currency
+					and party_account_currency != self.company_currency
+					and self.currency != party_account_currency):
+
 					frappe.throw(_("Accounting Entry for {0}: {1} can only be made in currency: {2}")
 						.format(party_type, party, party_account_currency), InvalidCurrency)