Problem at adding event template to an activity template

Dear all,

I followed the K2.net Studio SDK, created a Mail Server event template, then I created my own activity template (works fine), and tried to add the Mail Server template to it, but it doesn't work. K2 prompts out the following message:


I'm not sure the procedure that I added the event to activity is correct or not. In my activity, the Execute code is:

public bool Execute(K2Studio.Activity myActivity)
{
 base.Initialize(myActivity);
 myActivity.Description = this.MyTemplateDescription;
 AddDataField(myActivity);
 AddEvent(myActivity);
 return true;
}

The AddEvent(myActivity) is:

public void AddEvent(K2Studio.Activity myActivity) 
{
 K2Studio.Event myEvent = myActivity.Events.AddServerEvent("My Event Template");
 MyEventTemplate myEventTemplate = new MyEventTemplate();
 //myEventTemplate.BuildEvent(myEvent);
 myEventTemplate.Execute(myEvent);
}

The Execute code for the Event template is:

public bool Execute(K2Studio.Event myEvent) 
{
// Set the event template type
//myEvent.Type = K2Studio.EnumEvent.Server;
 PropertyTemplate.Instance = new PropertyTemplate();
 //base.PropertyTemplateAssists.Add(PropertyTemplate.Instance);
 //base.Initialize(myEvent);
 //myEvent.Name = this.MyEventTemplateName;
 myEvent.Description = this.MyTemplateDescription;
 //PropertyTemplate.Instance.LoadData();

 if (base.RunWizard(new TemplateWizard()) == System.Windows.Forms.DialogResult.Cancel) 
  {
     // If no Data present, remove Event from Activity else Save it
     if (!PropertyTemplate.Instance.HasData) 
     {
        myEvent.Activity.Events.Remove(myEvent.Name);
     } 
     else 
     {
       base.SaveAll(true);
      }
   } 
   else 
   {
      base.SaveAll(true);
    }
  return true;
}

I found the exception points are:
base.PropertyTemplateAssists.Add(...); base.Initialize(myEvent); PropertyTemplate.Instance.LoadData(); respectively.
When I commented out all these, the activity template can automate the Mail Server template, brings up the first page of the wizard form, but when I pressed "Next" to go further, K2 also prompts up the same error message.


Any help would be appreciated,
Cheers,
Patrick