Y'all are the best. Thank you for your support!
Yesterday I spent over an hour working with the embroidery teacher at the Bernina store where I bought my machine. She tried everything, eventually loading the design into her computer to see if she could find a problem using her Bernina embroidery software.
Alas the design was perfect - but it didn't look at all like what my machine was trying to stitch. AHA! Turns out you can't use the mega-hoop on my level of machine without processing the design through the software in order to break the design into three sections (top, middle, and bottom). So in order to make my $160 hoop work, I had to buy a $250 package of embroidery software, PLUS a PC computer 'cuz the software won't run on a Mac. GRRRRRRRRRRR!
Given that my goal is to make Christmas stockings for my two grandchildren, I'd been spending north of $500 (plus the cost of fabric, stabilizers, and thread). Something tells me I'd be a whole lot better off commissioning them on Etsy - or just using the regular size hoop and re-hooping.
What bothers me the most is that nowhere in the sales literature or in the mega hoop manual does it EVER tell you that you need the software. (In fact, software is never mentioned.) I think that's downright UNETHICAL on Bernina's part!
Thanks again for your patience and support!