Daily transactions not transfering

We are using Retail point of sale lite 2012/13, Administrator 2012/13 & Quickbooks plus 2012/13, the administrator system has developed a problem that it will not post the transactions to QB, we have had various error messages: error code 13, item in lists has no account (checked none found), and line error messages. The transactions are for general shop sales during the day, any transactions that have been entered against customer accounts are transfering but are creating multiple journal entries and invoices with the same reference numbers, any expense entries ie: write cheques are transferring correctly, all the general transactions are still visible on the POS transaction history