Unexpected Error when saving item receipt in NetSuite

Question

I got a new testing account in NetSuite, since my old account got expired. I created a parent company(US) with 2 subsidiaries in India. I created a purchase order using an indian subsidiary with item from Indian subsidiary. I clicked on 'receive button' and cannot save the item receipt due to the popup 'You cannot submit this form due to an unexpected error'. How can I solve this error? Custom workflows related to purchase order were suspended.