IIRC, to find your latest xml file. Go to where Mach was installed, in my case the C drive.
Click on "my computer", double click C drive, double click Mach3, look under xmlbackups, if you are using a mill, look for the highest numbered Mach3Mill.xb file. This is the latest xml used and saved on your machine. Select that file and use send to.
It might need renaming as mentioned above. Hope that helps