The rule looks ok but I can see where you might have a problem. The condition that you have for the rule is if the total number of unique items is greater than 1. The proper condition for this would be if total number of unique items was >= 1. This way even if you have only one item you will be charged. When I set the rule like this it works as expected for me.
One other thing I noticed is that you are charging a flat rate of 1.50 for the shipping, you mentioned that you would like this to be 1.50 for each item unless they purchase 50 worth or more. To make the shipping rule charge like this you should base the calculation portion off the subtotal of the quantity column, times 1.50. To account for totals 50 or more you can add in another condition to the trigger, you would base it off of the cart subtotal being less than 50.
I'm including a total of three screen shots for you on this so that you have a good reference for how these rules should be setup. Let us know if you have any further questions.
