Table error with Oracle 8i and BDE 5.01

I have a table:

CODIGO    NUMBER       4
NOME       VARCHAR2  35

I use the this.form.rowset.beginAppend()

Enter datas

If i delete this registry this.form.rowset.delete(), I have
succesfuly! But if i entry two CODIGO with some NUMBER exemple:

CODIGO = 1 - registry
CODIGO = 1 - other registry

then delete the registry, i receive this error:

Multiple records found, but only one was expected

Who is this?

Dario Basso Cardoso