Running Year End under the Maintenance menu will reset your batch number to 1. All batches must be posted or deleted before this can be done.

If the error batch represents a cheque (check) posted in AP, then I suspect that is why it can't be deleted. To find out what the error is print the batch listing report. Whatever it is, hopefully it can be corrected so that the batch can be posted. You will then need to post an adjustment as (I would assume) this transaction is not longer applicable to reconciling your bank balance.