This is a creepy one, I've managed to reproduce with just this one-liner:

 Code:
? "0.000001024 * 48845580 = " 0.000001024 * 48845580 " (Expected result: 50.01787392)"


I've tested with many versions of KiXtart (from 4.02 to 4.66), on Windows 7 and 10: result is always 0 when the user language is not in English. The system language has no impact.

Workaround:
Use a division instead of a multiplication, for example: 48845580 / 976562.5