I don't know if it'll help but I would write it like this:
[pascal]
data: array[0..400] of char;

procedure TForm1.ServerSocket1ClientRead(Sender: TObject;
Socket: TCustomWinSocket);
begin
datalength:=length(data);
ServerSocket1.Socket.ReceiveBuf(Data[0],datalength);
End;[/pascal]