Yes, I think it is related to the "parent" of accounts. First, you should check if the accounts mentioned in the error message ( account called "Period Opening Use" & "Prepayment" ) have their "parent"s. I have checked that if you go to "Accounting>>Configuration>>Accounts>>Account" and find out that the field of parent of account "Period Opening Use" is blank, this journal entry would not be posted. As a result, just go to "Accounting>>Configuration>>Accounts>>Account" and click "edit" to provide a "parent" for your "Period Opening Use" account.