[Plugin: Jazzy Forms] Invalid formula

Hey Igor,
Please disregard the earlier post I made about widgets. I got that handled. You might just post a reply to square anyone else away. However, I am using a new theme and my infomation in regards to the form has remained the same. The problem is I now get an Invalid Formula in the output box. The formula is simple it is:

(length * depth) + (length * width) + (length * width) + (width * depth) + (width * depth)

I do not see anything wrong with it. Like I said it also has not changed and used to work until I loaded up a new theme. What do you think?

https://www.ads-software.com/extend/plugins/jazzy-forms/