Setting default email Access Rights

I am attempting to set default Access Rights for new emails (inbound and outbound) for my Sale Department users.  Essentially, I want to ensure that all Sales Department members have Read Access to all emails generated by their department colleagues.

I use the Object Permissions UI page, setting the values for EmailDefRights.  I add my email profile as Record Author under the Use Record Permissions, set User or role who obtains permissions to Sales Department (user group), and check Grant Read access.  When I go to Apply the new setting, and request to change existing records, I get the following error:

"Object reference not set to an instance of an object."

And I cannot even leave the settings page.

What am I doing wrong?

BTW, I also tried this action on the Email message Permission, but nothing seems to happen.