All the failures you received were due to your not having Exception::Class installed ("Can't locate Exception/Class.pm in @INC"), and had nothing to do with the presense or absense of threads::shared.
in reply to Re: New Module Announcement: Object::InsideOut
in thread New Module Announcement: Object::InsideOut
As to your question concerning threads::shared, it is documented in the POD, namely, the application must use threads::shared;. t/03-threads.t is testing threads without object sharing and thus does not use threads::shared. However, t/04-shared.t does. Hope that helps.
Remember: There's always one more bug.