why didn't you say that in the first place :)

Based on the code, it looks like you're appending all the data each time, so I'd expect this error.
e.g.
first time ever - append 3 records
second time - 3 new records - appending 6 records - but 3 were already appended so you get the error

You need to add some code to make sure you're getting new records only.
e.g, Here's one way to do it

** vfp8
insert into targetTable ;
  select * from sourceTable ; 
    where sourceTable.id not in ( ;
       select id from targetTable)

** prior to vfp8
select * from sourceTable ; 
   where sourceTable.id not in ( ;
      select id from targetTable) ;
   into cursor cutmp
select targetTable
append from dbf("cutmp")

>Thanks
>
>But i see the same error : Uniqueness of index ... is violated .
>
>Any ideia ?
>
>Thanks