CalculatorPro doesn't work in sidebar

Hi I’m running WP 3.4.1 on a site, https://www.crockford.ca/products.

I got a calculator adapted by Calculator Pro. Here it is.
https://www.calculatorpro.com/calculator/materials-volume-estimator-calculator/

I cut and pasted the code into my sidebar widget as per the instructions, but it doesn’t work. Just goes back to the homepage when I plug in numbers.

I asked the coder for help and he said it must be something on my end, but he didn’t have anything else to offer. It works on the site (which it does.)

Any ideas?

thanks, Tamsen