Error when accessing Customize screen

Using the Highend WP theme, I am trying to access /wp-admin/customize.php via the button(s) under the Appearance menu. However, I have yet to be able to access the menu, and I receive the following error:

Warning: array_merge(): Argument #3 is not an array in /hermes/waloraweb038/b2337/moo.chadelliottorg/wp-includes/class-wp-customize-widgets.php on line 326 Warning: Invalid argument supplied for foreach() in /hermes/waloraweb038/b2337/moo.chadelliottorg/wp-includes/class-wp-customize-widgets.php on line 363 Fatal error: Cannot unset string offsets in /hermes/waloraweb038/b2337/moo.chadelliottorg/wp-includes/class-wp-customize-widgets.php on line 960

I have tried deleting then re-installing the theme (via FTP), but no luck. I’ve updated WordPress to the latest version, and I’m using Highend version 2.4.4. The Customize menu appears to work with other themes, but I don’t like any of them nearly as much as Highend. Any suggestions?