Yes this will crash. when you look on the troubleshooting page under "crash" you see that its the third most frequent beginners mistake listed there.

The fix:

Code:
ThisTrade = enterShort(1, myEntryPriceShort, myATR, 0, Spread);
if(ThisTrade) {
  MyEntryPrice = myEntryPriceShort; // The script is crashing here. When I quote it there is no crash.
  MyTradeSetBreakEven = 0;
}