Every job regardless of what's set to be nested?

Try a new job with a single piece of duct. Occasionally, you'll get an odd piece that can cause issues.

At what point does it crash?

Go to the folder the config points to (where MAP.INI is located) and delete the *.PRN files which for the printer configs. You'll then need to reset your printers but I've has corrupt PRN files cause crashes before, typically when it's processing prior to displaying the preview of reports.

The other thing you can try is changing the nesting algorithm.