Hello there! I have the same problem wirh Rack installation!
My computer is a 2009 MacPro with os 10.7.5.
I downloaded the Rack zip folder from the website, than I copied it into the application folder and than I extracted the file.
When I try to start the program (by clicking on the Rack file just extracted) it says: ‘Rack’s resource directory “n_0_290887/res” does not exist. Make sure Rack is correctly installed and launched.’ What can we do?
Thank you very much 
! Best regards.
Giuseppe