I duplicated the default theme so I could explore making changes and not lose updates if you update the default.

I created a new folder, renamed default.php, and changed the theme name in spTheme.txt.  I can activate the new theme just fine, but this error appears, then fades:

Fatal error: Cannot redeclare spdefault_textdomain() declared ../sp-resources/forum-themes/default/templates/spFunctions.php:18) in ../sp-resources/forum-themes/qbg/templates/spFunctions.php on line 19

Can you outline what I need to do just to rename the default theme?