AV on FinalizeDataOperations - Delphi5

[GrahamRola]

Delphi 5
Indy 10 5473

I call List in ftp component and it returns the appropriate data.
when the FinalizeDataOperation; is called I get an AV read of address 0xea5278ed.
I Put a breakpoint at the begin of GetResponse and looked at
the call stack (shown below);

What could possible be causing the AEncoding to be anything other
than Nil?  

Couple of other things of note.
When I place mouse over AAAllowedResponses   it only shows  (226) not ([226, 225, 250]);
There are 9 calls to GetResponse before this final call that all show Nil in AEncoding

Code:

procedure TIdFTP.FinalizeDataOperation;
...
  end else begin
    //ftp.marist.edu returns 250
    GetResponse([226, 225, 250]);  // call that generates AV
  end;
end;

Code:

function TIdTCPConnection.GetResponse(const AAllowedResponses: array of Int16;
 AEncoding: IIdTextEncoding = nil): Int16;
begin  // break point inserted here
  GetInternalResponse(AEncoding);
  Result := CheckResponse(LastCmdResult.NumericCode, AAllowedResponses);
end;

Call Stack
TIdTCPConnection.GetResponse((...),Pointer($55E4E3) as IIdTextEncoding)