Thanks for the feedback.

The following works well. However, I can't seem to get the fHighCurrent & fLowCurrent to work as Global vars..
Even if I place them in a seperate function outside of run.

Code
// Uncomment for crash.
//vars fHighCurrent = series(0, -LookBack);
//vars fLowCurrent = series(0, -LookBack);

function run()
 {
    set(PLOTNOW, TICKS);
    PlotScale = 8;

    StartDate = 20160101;
    EndDate = 20160331;
    BarPeriod = 60;
    LookBack = 50;

    vars Price = series(price());
    vars Highs = series(priceHigh());
    vars Lows = series(priceLow());
    var fHigh = FractalHigh(Highs, 3);	// short term highs and lows
    var fLow = FractalLow(Lows, 3);

    vars fHighCurrent = series(0, -LookBack);
    vars fLowCurrent = series(0, -LookBack);

    if(fHigh != 0){
      shift(fHighCurrent, fHigh, LookBack);
      plot("Recent High", fHighCurrent[0], MAIN|DOT, BLUE);
      printf(" fHighCurrent[0] = %.5f, fHighCurrent[1] =  %.5f  \n ", fHighCurrent[0], fHighCurrent[1]);
    }

    if(fLow !=0){
      shift(fLowCurrent, fLow, LookBack);
      plot("Recent Low", fLowCurrent[0], MAIN|DOT, RED);
      printf(" fLowCurrent[0] = %.5f, fLowCurrent[1] = %.5f \n ", fLowCurrent[0],fLowCurrent[1]);
    }
}