From the perspective of what I refer to as innovation methodology, I try to focus product and service designers on solving a problem for their potential customers. As applied to your HR centric product, I would encourage you to talk with people in that audience about what makes their job hard and what makes it easy. To the extent you solve their problems for them your product will be considered innovative.
Next deconstruct those people in to various groups who are part of the process, and ask each of them the same questions related to problems which can be solved. HR might be deconstructed into groups of Recruiters, Hiring managers, Compensation managers (people who create the packages to bring in top talent), Staff managers, and HR generalists who usually support the staff managers. Each will likely give you a different perspective on the topic and potential to create a tool to solve their problems.
I want to credit Hans for stating this (somewhat differently), but it is important to recognize that people will almost always give you an answer that is not insulting or hurtful, so you will often get answers biased toward your product being good as it is. I would suggest you focus on watching them react (video if they will allow it). You will often see a "sour" face followed up by a verbal compliment. Most people don't even realize they are not being 100% accurate to how they really felt, so just know the human decency bias exists.
(again +1 to Hans) Always put something in their hands to touch, even if it is just a mock up with pictures of buttons rather than something that works. Prototypes are critical and you should only test one or two features at a time. Tell the viewers what to ignore. (i.e. "This is not the real case we will use for our widget, so I am interested in seeing how you might use this menu during your daily task of __."
Just as another common pitfall, don't ask for input on how to make something innovative. Almost as a universal rule, people giving feedback can not provide answers that our outside their current world view. As such, they have a hard time envisioning a world after a disruptive innovation. Imagine asking people to imagine a world with the iPhone back when our cell phones were the size and shape of a typical masonry brick. Again what they are great experts on is the tasks they do during their daily lives, and the problems the might be having. Your task is to make the innovative tools that will help them with those problems.