TDateTime(Data) := TMyRecord(List[Index]).Date;

  function NativeToDateTime(DataType: TFieldType; Data: TDateTimeRec): TDateTime;
  var
    TimeStamp: TTimeStamp;
  begin
    case DataType of
      ftDate:
        begin
          TimeStamp.Time :=  0 ;
          TimeStamp.Date := Data.Date;
        end;
      ftTime:
        begin
          TimeStamp.Time := Data.Time;
          TimeStamp.Date := DateDelta;
        end;
    else
      try
        TimeStamp := MSecsToTimeStamp(Data.DateTime); // Попадает сюда
      except
        TimeStamp.Time :=  0 ;
        TimeStamp.Date :=  0 ;
      end;
    end;
    Result := TimeStampToDateTime(TimeStamp); // и здесь возникает ошибка 
  end;

function TimeStampToDateTime(const TimeStamp: TTimeStamp): TDateTime;
asm
        PUSH    EBX
{$IFDEF PIC}
        PUSH    EAX
        CALL    GetGOT
        MOV     EBX,EAX
        POP     EAX
{$ELSE}
        XOR     EBX,EBX
{$ENDIF}
        PUSH    EAX
        CALL    ValidateTimeStamp // Вот тут вот
        POP     EAX
        MOV     ECX,[EAX].TTimeStamp.Time
        MOV     EAX,[EAX].TTimeStamp.Date
        SUB     EAX,DateDelta
        IMUL    [EBX].IMSecsPerDay
        OR      EDX,EDX
        JNS     @@ 1 
        SUB     EAX,ECX
        SBB     EDX, 0 
        JMP     @@ 2 
@@ 1 :    ADD     EAX,ECX
        ADC     EDX, 0 
@@ 2 :    PUSH    EDX
        PUSH    EAX
        FILD    QWORD PTR [ESP]
        FDIV    [EBX].FMSecsPerDay
        ADD     ESP, 8 
        POP     EBX
end;

      try
        TimeStamp := MSecsToTimeStamp(Data.DateTime); // Попадает сюда
      except
        TimeStamp.Time :=  0 ;
        TimeStamp.Date :=  0 ;
      end;
    end;

TimeStamp := MSecsToTimeStamp(Data.DateTime);