Hi there Rob. Thanks for reaching out and sorry to hear you’re having issues. It definitely sounds like something is up. Is it possible you have an old version of the PRO release active/installed on your site? If so you’ll want to deactivate it (no need to fully delete) to make room for the new release.
If you do still see the message that the folder exists, please rename the zip file on your computer and try again. I’d also open your FTP client to see if the folder shows up there but not on the WP side (which is definitely possible). Give that a go and let me know if you’re still having issues from there.