Error on localhost

Hello Ionut

Which versions are you using? Please mention for PHP, Helix Ultimate, SP Page Builder.

Best regards

PHP 8.1 is not fully supported yet in Helix, so use PHP 8.0.x
OR make this change:

public function count_modules($position)
{
    $position = Helper::CheckNull($position);
    return ($this->doc->countModules($position) || $this->has_feature($position));
}