nimporter can't find file on Windows 10
Here is a working example to reproduce the problem:

C:\Users\dave.sisk\math_speedup_example>type pmath.py
def fib(n):
    if n == 0:
        return 0
    elif n < 3:
        return 1
    return fib(n - 1) + fib(n - 2)

C:\Users\dave.sisk\math_speedup_example>type nmath.nim
import nimpy

proc fib(n: int): int {.exportpy.} =
    if n == 0:
        return 0
    elif n < 3:
        return 1
    return fib(n-1) + fib(n-2)

C:\Users\dave.sisk\math_speedup_example>type main.py
import nimporter
from time import perf_counter
import nmath  # Nim imports!
import pmath
print('Measuring Python...')
start_py = perf_counter()
for i in range(0, 40):
    print(pmath.fib(i), end=" ")
end_py = perf_counter()

print('\n\nMeasuring Nim...')
start_nim = perf_counter()
for i in range(0, 40):
    print(nmath.fib(i), end=" ")
end_nim = perf_counter()

print('\n---------')
print('Python Elapsed: {:.2f}'.format(end_py - start_py))
print('Nim Elapsed: {:.2f}'.format(end_nim - start_nim))


C:\Users\dave.sisk\math_speedup_example>python main.py
Traceback (most recent call last):
  File "C:\Users\dave.sisk\math_speedup_example\main.py", line 3, in <module>
    import nmath  # Nim imports!
  File "<frozen importlib._bootstrap>", line 1027, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1002, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 945, in _find_spec
  File "C:\Users\dave.sisk\AppData\Local\Programs\Python\Python310\lib\site-packages\nimporter.py", line 1269, in find_spec
    return Nimporter.import_nim_code(fullname, path, library=False)
  File "C:\Users\dave.sisk\AppData\Local\Programs\Python\Python310\lib\site-packages\nimporter.py", line 944, in import_nim_code
    NimCompiler.compile_nim_code(
  File "C:\Users\dave.sisk\AppData\Local\Programs\Python\Python310\lib\site-packages\nimporter.py", line 705, in compile_nim_code
    cls.check_compile_errors(errors, library, nim_args, output, tmp_cwd, warnings)
  File "C:\Users\dave.sisk\AppData\Local\Programs\Python\Python310\lib\site-packages\nimporter.py", line 492, in check_compile_errors
    raise NimCompileException(errors[0])
nimporter.NimCompileException: Error: unhandled exception: The system cannot find the file specified.

