I am trying to make a parameterized blueprint in sandbox mode, but it won't allow me to access any variables of parameters higher in the list. All I get is an error, and it doesn't work. It doesn't show in the image, but I get the error no matter which parameter I enter into the formula.

I first crafted a rare quality spidertron, and did not receive the achievement. I assumed it had to be a common spidertron, so I made one in an assembler, and still nothing. Lastly, I crafted a common one by hand, and I still did not earn the achievement. I'm unsure of what to do, so if anyone knows ...