I have not had that for a long time
after that the game freeze
If you can, please send us a savegame of this state so we can have a look what is causing the error that keeps the calculator from giving you values! 
you can send it to support@camshaftsoftware.com mentioning this thread. Zip it if necessary.
Sorry, no savegame, cause i have to quit the game with the taskmanager.
The ram was up to 97% and my computer has 32GB 