When I try to create a Posix Group using the posixaccount zimlet I get the following error:

"Server error encountered Message: createLDAPEntry invalid attr name: [LDAP: error code 17 - memberUid: attribute type undefined] Error code: account.INVALID_ATTR_NAME Method: [unknown] Details:soap:Sender"

We're running Zimbra 7.2 and I installed the latest posixaccount.