Error When Updating via Datagrid

hi all

i got this code that populate my datagrid
[VBCODE]sSQL = "SELECT [Artikel], [HPP], [HPP_baru] FROM barang"
rsBrg.CursorLocation = adUseClient
rsBrg.Open sSQL, Conn, adOpenDynamic, adLockOptimistic

Set dgBarang.DataSource = rsBrg
dgBarang.Refresh[/VBCODE]
i set the AllowUpdate properties for the Datagrid to TRUE
when i changed the first column(Artikel) which is the PK, it went smooth..but when i changed the 2nd and 3rd column, an error raised

Quote:

Row cannot be located for updating. Some values may have been changed since it was last read

anyone have any clues?

PS : the database is located at my local hard drive (for testing purpose), and the value doesn't changed by anyone

thanks