Try this:

Code:
function run()
{
	vars Price = series(price());
	vars maFast = series(SMA(Price, 50));
	vars maSlow = series(SMA(Price, 200));
	
	vars entries = series(0);
	
	if(crossOver(maFast, maSlow))
	{
		entries[0] = 1;
		if(Sum(entries+1, 6) == 0)
			enterLong();
	}
	
	if(crossUnder(maFast, maSlow))
	{
		entries[0] = 1;
		if(Sum(entries+1, 6) == 0)
			enterShort();		
	}
	
}


This script stores each crossing of the moving averages in a series. The current value of the series is 1 if there was a cross, and 0 if there was no cross. We then shift the series backwards by one bar and sum the number of crosses in the previous 6 bars. We shift the series backwards by one bar in order to exclude the current cross from the summation. If we didn't do this, the script would never enter a trade since the if(Sum(...)) statement would always be true.

Hope that helps.

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