Yup, I get those periodically, and got one today on M3.m1s. The fix is usually to open the offending file with Notepad, and you should see a few garbage characters at the end of the file. Delete those, and save it, and the problem should go away.
spindlespeed.m1s does actually have a syntax error in it, in some versions of Mach3, yet it does not always generate an error message.
Regards,
Ray L.