diff --git a/erpnext/accounts/doctype/purchase_invoice/purchase_invoice.py b/erpnext/accounts/doctype/purchase_invoice/purchase_invoice.py
index 4d58f98..530d08a 100644
--- a/erpnext/accounts/doctype/purchase_invoice/purchase_invoice.py
+++ b/erpnext/accounts/doctype/purchase_invoice/purchase_invoice.py
@@ -204,7 +204,7 @@
 		if frappe.db.get_value("Buying Settings", None, "po_required") == 'Yes':
 			for d in self.get('items'):
 				if not d.purchase_order:
-					throw(_("Purchse Order number required for Item {0}").format(d.item_code))
+					throw(_("Purchase Order number required for Item {0}").format(d.item_code))
 
 	def pr_required(self):
 		stock_items = self.get_stock_items()
diff --git a/erpnext/public/js/controllers/transaction.js b/erpnext/public/js/controllers/transaction.js
index cbedf80..7f0e917 100644
--- a/erpnext/public/js/controllers/transaction.js
+++ b/erpnext/public/js/controllers/transaction.js
@@ -500,6 +500,7 @@
 	},
 
 	get_exchange_rate: function(transaction_date, from_currency, to_currency, callback) {
+		if !(transaction_date && from_currency && to_currency) return;
 		return frappe.call({
 			method: "erpnext.setup.utils.get_exchange_rate",
 			args: {
@@ -762,7 +763,6 @@
 			if(calculate_taxes_and_totals) me.calculate_taxes_and_totals();
 			return;
 		}
-
 		return this.frm.call({
 			method: "erpnext.accounts.doctype.pricing_rule.pricing_rule.apply_pricing_rule",
 			args: {	args: args },
@@ -1117,4 +1117,4 @@
 
 		return method
 	},
-});
\ No newline at end of file
+});