Close...it was this one:
/httpdocs/templates/shaper_helixultimate/html/com_sppagebuilder/form/bak_edit.php
So all you did was rename "edit.php" to "bak_edit.php". You didn't actually edit any of the file contents. That was not clear in our communication. Anyway...I've renamed the same file from my live site and now that works too.
Thanks for fixing it, it's unfortunate it took this long and could have been resolved much more quickly. I've noticed that Joomshaper techs want to jump in and fix things, rather than explain the problem and point their customers to possible solutions first. A little education goes a long way.
As the wise man said, if I'm hungry, don't give me a fish...teach me how to fish!