Record not found ... error

Please Help,

I'm receiving a "Record not found or changed by another user" error when I
try to edit a record within a local database.  The database has been copied
from another machine to my pc for development purposes but I am unable to
edit any of the values (unless I manually edit the record via the console,
post, commit and refresh).  Can change the values using ISQL but still can't
edit them from my application

Anything obvious ?

This is a very simplified version of my code (which doesn't work either)
The param I am passing is a reference no.

procedure TForm1.Button1Click(Sender: TObject);
begin
  IBCDS1.Params[0].AsInteger := StrToInt(Edit3.Text);
  try
    IBCDS1.Open;
    IBCDS1.Edit;
    IBCDS1STATUS.Value := StrToInt(edit1.text);
    IBCDS1.Post;
    if IBCDS1.ApplyUpdates(0) = 0 then
      Caption := 'Status = ' + edit1.Text
    else
      Caption := 'Status Change Failed';
  finally
    if IBCDS1.Active then
      IBCDS1.Close;
  end;
end;