Not a repository, per se ... but a full site backup consisting of an SQL dump of the DB, an archive of the data directory, and an archive of the code directory could be 'migrated' (the term Moodle uses) to another machine.
Just because you can create those and down load those doesn't mean they alone will run a Moodle locally. They require: apache server, mysql server, and php and might require higher versions of apache, mysql, and PHP.
Which leads to the next question ... I see iMac ... does the iMac have the same version of Moodle on it as the production server version? (Site Admin Menu, Notifications on both will show version).
Then again, if you'd share info concerning versions ... a backup from a 2.8.x won't work on a 2.4, I don't think. If they are at least the same series ... ie, both 2.8.x then it could have something to do with the config/setup on the iMac, but since no user has 'Vulcan Mind Meld' abilities ;), doubt of anyone could say for sure. So: 1. what does the error say? 2. Have you turned on debugging for full output of the error and looked at that?
'spirit of sharing', Ken