Invoice

Hi, I have aregistrar in my fred db, The registrar is working fine as he has credits and if he registrer domains credits are deducted fine. But I want to add a new registrar. I have already created a new registrar who,assing zones and the invoice_prefix has values that whre used in the previous registrar. Now if I add the credit to this new registrar It gives me an error that duplicate entries in the invoice table. I suspect its due to the field prefix of the invoice table. What am I supposed to do?Because the Invoice table contains the records created while adding credit for the 1st registrar? Do I have to flush out the data in the table invoice so that I can enter data for my new registrar?? If I flash and a registrar issues info_credit what will he see??? Regards, Bryton.