eMMC errors

[MrFawlty]

I am trying to setup Openmediavault onto my newly purchased Rock64.  I bought the USB eMMC adaptor to ease installations and I can write the image with no errors using the Pine64 Etcher application, but when I insert it and turn on my Rock64, I get the errors in the attached image (Sorry, I don't have any other way to capture it other than taking a picture with my phone.)

I have tried the following:

• Removing and re-inserting the eMMC, making sure the contacts are clean
  
• wiping it and reinstalling
  
• On my Windows PC, 'cleaning' the disk completely and checking it for errors using the USB adaptor
  

What else should I be doing?

N00b question alert: The jumper on the board is only to be used IF you want to boot from SD Card, correct? You leave it open if you want to boot from eMMC?

Thanks in advance.

Daniel