Exception 'Uneven size in DecodeToStream'

Using Indy 9.03, I have the MailDemo working and when I am getting the
messages I get an
Exception 'Uneven size in DecodeToStream.' in message 62 of 212.

Here is the offending code:

procedure TIdDecoder4to3.DecodeToStream(AIn: string; ADest: TStream);
type
  ThreeByteRec = record
    case Integer of
     0: (Bytes : array[1..3] of Byte);
     1: (ThreeChars : array[1..3] of Char);
     2: (TwoChars : array[1..2] of Char; Waste1: Char);
     3: (OneChar: Char; Waste2: array[1..2] of Char);
  end;
var
  LBOut: ThreeByteRec;
  LOut: string;
  LUnit: TIdCardinalBytes;
  LInSize, LInPos : Integer;
  LOutBuf : String;
begin
  if (Length(AIn) mod 4) > 0 then begin
    raise EIdException.Create(RSUnevenSizeInDecodeStream); { here is the
error }
  end;

Then, I used Outlook without errors and I can't more locate the message text
with problems to Post.

Is there any fix?

Luiz.