I got this err when I converted the program to .exe when it was .py, there was no problem.
db.bind(provider='sqlite',
filename=(r'D:\pythons\trainers-salaries-calculator'
r'\trainers_salaries_calculator.sqlite'),
create_db=True)
If you using pyinstaller, add attribute --hidden-import pony.orm.dbproviders, when compiling, like so: pyinstaller --hidden-import pony.orm.dbproviders your_script_path.py