Further to this post on this error. Here is another reason why this error occurs. If you happened to use the seeded accounting rule called Immediate in your transaction (be it in Service Contract or Sales Order) you need to make sure that the period type used in ledger or set of books matches to the Period type used in Immediate accounting rule.

As you can see below, Immediate accounting rule comes with period type called Month (this cannot be changed). Say in your implementation you do not use Month as your period type but something else like 4-4-5 or Monthly.  In that case, if you bill a contract or invoice an order line with Immediate accounting rule, you are bound to get this error when you run autoinvoice import.

To get around this, you need to define your own accounting rule with your period type that matches to your ledger. When use that accounting rule, phew, that error goes away.