Also, if you're still having issues, some things to check:
1) Make sure that the USB cable is plugged in all the way, both on the robot and on the Chromebook. The little red light on the controller board should be on.
2) Make sure that you select the "noggin" setting on the drop down on the website.
If issues continue, can you send me a picture or screenshot of what it looks like when you are trying to upload? I'm out and about today, but we can also schedule a zoom session to debug it together tomorrow or later this week.