So I had a client who has 2 hub servers and 3 mailbox servers. Exchange is housed in the parent domain and they have a child domain. The complained that the Offline address book was not synchronizing properly since the migration to exchange 2010 occurred from old and dusted groupwise.
Sure there are tons of posts with this specific issue and several blogs say check DNS, addressing issues, registry , etc (source: http://blogs.msdn.com/b/dgoldman/archive/2007/11/15/oab-generation-fails-to-generate-with-errors-9330-and-9334.aspx ).
The event logs on the server generating the OABs in my case were exactly the same messages as the post above; the only thing to note was the, server that was failing, was being referenced was the DC in the child domain. A packet capture I had done initially showed traffic being passed to the correct server. So I went down a rabbit hole that didn't pan out. As it turns out that in other logs the FQDN of this server was referenced but NOT for the OAL gen process. So I appended the child domain name to the DNS suffixes in the order of parent domain, child domain.
Updated the OAB again and successfully resolved the issue.
OABGen encountered error 80040115 while initializing the offline address book generation process. No offline address books have been generated. Check the event log for more information.
OABGen encountered error 80040115 (internal ID 50004b2) accessing Active Directory