...Windows 10 italian version...
https://sourceforge.net/projects/trurl/
The point is that jwdietrich wrote a very good rpn engine, which is the bases for any calculator.
...One thing: the app saves a .txt and a .ini files with name in cyrillic characters. That names appears as "????.txt" and "?????.ini" on a not-cyrillic fonts machine, as my pc.It could be useful to save using the local character set of the machine...
I wonder if it is possible that your Windows does not have Cyrillic letters?