Although I have never had a report of this issue and tutorial and sample app are known to work, it is possible that the issue is due to using an old version of Xcode, in the event that the current version which is used to build the frameworks is using an optimization that is somehow not backwards-compatible. I’m a bit skeptical that that’s the issue, but you can check it out and see.
I would recommend going through standard troubleshooting procedures: throw out the project and the downloaded OpenEarsDistribution, quit Xcode, and delete the contents of DerivedData, then restart your Mac and download a fresh version to follow the tutorial for. If that doesn’t work, I would just upgrade to the current Xcode since it’s free and you’re on Yosemite.