Mach will only run the file it is being given, if that file is essentially blank then Mach will do nothing.
If you open your file you created out with Mach, in notepad, you will see it is exactly the same.
I have never used SheetCAM so cant help with it but looks to me like you are not defining the toolpath in sheetcam correctly or possibly you are using the wrong post processor in sheetcam.
Hood