I'm using WordPress 4.5 and/or PHP7 and my theme is broken.
Open the functions/admin/option-generator.php file and locate line 38 which looks like this:
$out .= $this->$option['type']( $option );
Change that line so it looks like this:
$out .= $this->{$option['type']}($option);
Next open the functions/admin/metaboxes-generator.php file and locate line 48 which looks like this:
$out .= $this->$value['type']( $value );
Change that line so it looks like this:
$out .= $this->{$value['type']}( $value );
Finally, open the functions/admin/shortcode-generator.php file and locate lines 116 and 122 which both look like this:
$out .= $this->$option['type']( $option );
Change that line so it looks like this:
$out .= $this->{$option['type']}( $option );
Save the files and empty your caching (including caching plugins) and that should fix it.