NPE editing group when Center hierarchy turned off

Get NPE when clicking "Edit Group information" on group created on instance that has Center hierarchy turned off.

Repro steps:
1. Set custom property:
ClientRules.CenterHierarchyExists=false
2. Start mifos.
3. create Group, including meeting information. Submit.
4. Click Edit Group information.

Actual result:
NPE in org.mifos.customers.group.struts.action.GroupCustAction.manage(GroupCustAction.java:245)
see attached screen.

Expected result:
Edit group screen.