Данная ошибка вызвана недостаточными правами пользователя в рабочем каталоге.
Решение
Either you can open RFEM with the right-click and using the option "Run as Administrator" or assign the access rights for the working directory using Windows Explorer. You can find the path of the working directory in RFEM under "Options" → "Program Options" → "Data Files" → "Working Directory."