The following code gives me exception. Please help me
....
SimpleDateFormat dateFormat = new SimpleDateFormat("dd/MM/yyy HH:mm:ss");
dateFormat.setTimeZone(TimeZone.getTimeZone("GMT"));
Date dateFrom = dateFormat.parse("01/08/2008 00:00:00");
Date dateTo = dateFormat.parse("31/08/2011 00:00:00");
Instrument instrument = Instrument.EURUSD;
long fromTime = dateFrom.getTime();
long toTime = dateTo.getTime();
double[][] fractal = indicators.fractal(instrument, Period.ONE_HOUR, OfferSide.ASK, 2, fromTime, toTime);
...

Exception thrown while running onMessage method: Interval from [2008.07.31 22:00:00 000] to [1969.12.31 23:00:00 000] GMT is not valid for period [Hourly]

We were not able to reproduce the error. We tried with the following strategy:

package jforex.bugtests;

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.TimeZone;

import com.dukascopy.api.IAccount;
import com.dukascopy.api.IBar;
import com.dukascopy.api.IConsole;
import com.dukascopy.api.IContext;
import com.dukascopy.api.IEngine;
import com.dukascopy.api.IIndicators;
import com.dukascopy.api.IMessage;
import com.dukascopy.api.IStrategy;
import com.dukascopy.api.ITick;
import com.dukascopy.api.Instrument;
import com.dukascopy.api.JFException;
import com.dukascopy.api.OfferSide;
import com.dukascopy.api.Period;
import com.dukascopy.api.IEngine.OrderCommand;

public class FractalTest2 implements IStrategy {

   IIndicators indicators;
   IContext context;
   IConsole console;
   IEngine engine;
   
   @Override
   public void onStart(IContext context) throws JFException {
      
      indicators = context.getIndicators();
      this.context = context;
      console = context.getConsole();
      engine = context.getEngine();
      
      //submit an order just to cause onMessage to get called
      engine.submitOrder("order1", Instrument.EURUSD, OrderCommand.BUY, 0.001);
   }
   
   @Override
   public void onMessage(IMessage message) throws JFException {
      calcFractal();
   }
   
   private void calcFractal() throws JFException{
      SimpleDateFormat dateFormat = new SimpleDateFormat("dd/MM/yyy HH:mm:ss"); 
      dateFormat.setTimeZone(TimeZone.getTimeZone("GMT")); 
      Date dateFrom = null;
      Date dateTo = null;
      try {
         dateFrom = dateFormat.parse("01/08/2008 00:00:00");
         dateTo = dateFormat.parse("31/08/2011 00:00:00");
      } catch (ParseException e) {
         context.getConsole().getErr().println(e);
      }

      Instrument instrument = Instrument.EURUSD;
      long fromTime = dateFrom.getTime();
      long toTime = dateTo.getTime();
      
      double[][] fractal = indicators.fractal(instrument, Period.ONE_HOUR, OfferSide.ASK, 2, fromTime, toTime);
      context.getConsole().getOut().println(fractal[0][0]);
   }

   @Override
   public void onTick(Instrument instrument, ITick tick) throws JFException {}

   @Override
   public void onBar(Instrument instrument, Period period, IBar askBar, IBar bidBar) throws JFException {}

   @Override
   public void onAccount(IAccount account) throws JFException {}

   @Override
   public void onStop() throws JFException {}

}

Thanks for answer, but I receive the exception. I found a working solution, when I move the code from onMessage to onTick it works properly.