How to check if record is locked (again)

I submitted this question a couple of days ago:

How can you check to see whether a record that you are about to write to is locked by another user? If I have to check for an exception, then which one should I check for (EConvertError, E....)? What I want to do is rollback a Transaction if my write to a table fails.

and got this response from Waldek:

You must check for exception EDBEngineError and then
test ErrorCode like this
  case Errors[0].ErrorCode of
    DBIERR_LOCKED:{ Action , if lock failed}
    DBIERR_UNLOCKFAILED: { Action , if unlock failed}
  end;

The code doesn't compile and I was wondering if Waldek, or anybody who gets this, could help me out again?
       
The following code works but will report the same error when ANY kind of EDBEngineError Exception occurs. Can you tell me (or even better, show me) how to modify it to test specifically for a locked record? It would help me out a lot.

procedure TFRMMain.Button2Click(Sender: TObject);
begin
  try
    ItemsTable.edit;
    ItemsTable['Test']:=1;
    except on EDBEngineError do
      showmessage('Record is locked !');
  end;
end;

I want to know how I can extract the specific error condition that has occured.