InteractiveBrokers-Option-Test

Trying a plane vanilla option Buy Call transaction using below code from the options blog (brilliant by the way!). The code is able to find the option symbol and displays the underlying symbol; however stops with an error at "placetrade (line 49). IB is connected in order manager. Obviously I must be doing something wrong - any suggestions ? Thank you

CODE:
using WealthLab.Backtest;
using System;
using WealthLab.Core;
using WealthLab.Data;
using WealthLab.Indicators;
using System.Collections.Generic;
using WealthLab.InteractiveBrokers;

namespace WealthScript1
{
   public class ATMOption : UserStrategyBase
   {
      public override void Initialize(BarHistory bars)
      {
         double price = bars.Close[bars.Count - 1];
         DateTime currentDate = bars.DateTimes[bars.Count - 1];
         int minDaysToExpiry = 5;
         bool weeklies = false;
         bool closestStrike = true;
         bool allowExpired = false;
         string optSym = IBHistorical.Instance.GetOptionsSymbol(bars, OptionType.Call, price, currentDate, minDaysToExpiry, weeklies, allowExpired, closestStrike);
         DrawHeaderText("ATM Call: " + optSym, WLColor.NeonGreen, 14);

         if (bars.Scale.IsIntraday)
         {
            _obars = GetHistory(bars, optSym);
         }
         else  // assuming Daily
         {
            // request 3 months of 30 minute bars and synchronize with the non-intraday scale
            _obars = WLHost.Instance.GetHistory(optSym, HistoryScale.Minute30, currentDate.AddMonths(-12), currentDate, 0, null);
            if (_obars != null)
            {
               // compress to Daily bars
               _obars = BarHistoryCompressor.ToDaily(_obars);

               // sync the bars with the non-intraday data
               _obars = BarHistorySynchronizer.Synchronize(_obars, bars);
            }
         }

         if (_obars == null)
         {
            WriteToDebugLog("Could not get option data, check the Log Viewer for more info.");
            return;
         }
         else
         {
            PlaceTrade(_obars, TransactionType.Buy, OrderType.Market, 0, 1, "Buy Call");   // Position Tag 1
         }


         PlotBarHistory(_obars, optSym);
      }

      //execute the strategy rules here, this is executed once for each bar in the backtest history
      public override void Execute(BarHistory bars, int idx)
      { }

      BarHistory _obars;      // the option's BarHistory
      int _hash = -1;

   }
}