How is BILLNO generated?


>Hi,
>
>I have developed a Billing System in VFP 6.0 which is installed in WIN'98 environment and network is Peer-to-Peer. The software is multiuser.
>
>The table is BILL.DBF which have two candidate index on field BILLNO and DOCKETNO.
>
>In the entry form, I have not included the table in DATAENVIRONMENT but open it with USE [table name] EXCLUSIVE command and after appending record I close it with USE command.
>
>But I have observed that more than one record with same BILLNO ( index on BILLNO is candidate). I don't understand why this is happening. Please suggest me some solution - How to get rid of this problem.
>
>Note: if I issue the reindex command, it generate an error of "INVALID DATABASE". Then I validate the database but after sometime it gives the same error.
>
>Thanks
>Aritra