I'd research prior discussions like this.

1. https://www.google.com/search?q=Call+stack+Microsoft.Exchange.Data.Directory.SystemConfiguration.AddressBookBase.GetAllRoomsAddressList%28ClientSecurityContext+clientSecurityContext%2C+A&ie=utf-8&oe=utf-8

2. Lead me to https://social.technet.microsoft.com/Forums/exchange/en-US/8ae2da35-1fb7-4969-a6f2-b108a2988612/owa-addressbook-error which claims they fixed it at...

3. http://blogs.msdn.com/b/dgoldman/archive/2007/12/05/deleting-the-all-rooms-address-list-stops-it-from-showing-up-in-owa.aspx

I no longer have access to OWA but hope sharing how to research such issues saves you a call to Microsoft.
Bob