How do I configure to a group have access to the process?

I have a process where I need to set up a group to have access to this task. I already have the group created in my organization and I already have members in this group, but when I execute the process the following error occurs:

https://drive.google.com/file/d/0B8aMiLwwVY0nVHVGSElmZ3R3YW8/view?usp=sharing

Here’s the example of how I assign a user to the group:

https://drive.google.com/file/d/0B8aMiLwwVY0nWnFGN0JsSzJ6ZkE/view?usp=sharing

And here’s how I set up the group to have access to the process:

https://drive.google.com/file/d/0B8aMiLwwVY0nSEkxdVZRWFdubUU/view?usp=sharing