When recording an inventory transaction, an error stating AccountIdNull or AccountNull error may appear. This error seems to occur if the transaction contains an inventory item which is set up as I Buy This Item and I Inventory This Item. To check this, go to the Inventory command centre and click Items List then click the zoom arrow to open the item.
To fix this error
We've found that by selecting the option I Sell This Item within the item can resolve this issue. You'll also need to choose a Cost of Sales Account and Income Account for Tracking Sales. Providing you'll never actually sell the item, it doesn't matter which accounts you select. If unsure, you can create new accounts for this purpose.
To exclude the item from sale
We realise that this workaround could create problems if you accidentally sell an item that you don't ordinarily sell. To prevent this, you can label the item number as not for sale or you can make the item inactive, so it doesn't appear in selection lists: