1) Find out the Business Group to which your operating unit is assigned to. You can do that by going to Accounting Setup screen in GL. Query your ledger and go to Operating Unit option. The screen will tell you to which Business Group your operating unit is assigned to.
2) Using System Administration responsibility set the values of following two profile options at Site level, to the Business Group associated with your operating unit. (You can also set these options for the responsibility "Inventory":)
HR: Business Group
HR: Security Profile


While setting up the HR: Business Group ; I'm not able to update it.Screen seems like frozen.