This is the button click procedure I used and I get no error when the patch
I suggested is applied:

procedure TForm11.Button4Click(Sender: TObject);
var
qry_tmp : TIB_Query;
Begin
qry_tmp := TIB_query.Create(Self);
try
qry_tmp.SQL.Add( 'select *' );
qry_tmp.SQL.Add( 'from rdb$database' );
qry_tmp.SQL.Add( 'where rdb$relation_id = :w' );
qry_tmp.Params[0].asInteger := 5;
// qry_tmp.ParamByName('w').asInteger := 5;
qry_tmp.Open;
finally
qry_tmp.Free;
end;
ShowMessage('No error');
end;

Regards,
Jason LeRoy Wharton
www.ibobjects.com