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 line 122 which looks 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.