MinGW and WinSCP scripting mode interaction

I have a simple my_scrip.txt file (option batch on ... etc.) which works perfectly from a DOS window (see command below):
But the same command doesn't work from a MinGW/MSYS windows (cf. "Host does not exist").

I tried all I can imagine (single-quotes, double-quotes, backslashes) but nothing works.

This FAQ may help you:
My script works fine when executed manually, but fails or hangs when run by Windows Scheduler, SSIS or other automation service. What am I doing wrong?

Try this:
Or even better: