Hello, @sjd, and welcome to the Seamly2D forum.
This error seems to be the same as one that was posted a few days ago. @slspencer posted a solution that may help you. You will find it here: Formula assistant crashes program - #8 by slspencer
Please try this fix and let me know if it works for you. If it doesn’t, we’ll need to get someone to help you further.
Thank you.