If I'm using inheritance, could a 'protected' error still occur? How?

Yes. If a subclass incorrectly attempts to redefine a `protected` property with a different access modifier (like `public` or `private`), or if it tries to use `protected` in an invalid context within its own methods, the error can occur. Subclasses inherit the `protected` access level, so you can't change it during redefinition. Also, ensure you're correctly referencing the inherited protected property using `$this->propertyName` or `parent::propertyName`.