If this is the only one you are having trouble with you should print out the values you are using in this rule to see what they are when you get to the confirm page. On your confirm page you can add in the following code to view these values:
print("the total of the items in the cart is: " . $eCart1->TotalColumn('TotalPrice') . "<br/>" . "the checkout country is: " . $_SESSION['eCartCheckoutForm_shipping_country']);
Also, one other thing that I noticed is that you have the other rules setup for < 100, because of this the final rule should be looking for >= 100. If the total was exactly 100 neither rule would trigger.