Yosemite(Mac OSX 10.10) uses a completely different library setup than the rest of OSX(<=10.9.6).
This setup breaks backwards compatibility with many applications.
For this reason.. it is not yet supported..
If you're running OSX 10.10 Yosemite and wish to run the GoldCoin (GLD) client, I suggest you try to run the client in a VM or await the release of our Java client.
Sorry for any trouble on your end.. but it isn't our fault that they decided to do this and the modification required to make it work on 10.10 would likely break the binary on 10.9 and lower.