Account is Empty. Do you want to save changes with errors?

Hello,

I am entering a sales return in under the 'Sales Transaction Entry' function and when I try to save the entry, I continue to get a pop-up noting 'Account is empty.  Do you want to save changes with errors?'.

I have checked the inventory cards for each item and I have filled in all the necessary information, including the account allocations.  I do not get the pop-up message when I am entering the same inventory items when creating an invoice.

Any GP experts out there that have insight?

Thanks!