I've downloaded bitnami erpnext installer for OS X and follower the instructions. Then restarted my mac, restarted servers, turned off firewall and check that servers are running.
Then I went to localhost:8080/127.0.0.1:8080 and got the error:
"Internal Server Error
The server encountered an internal error or misconfiguration and was unable to complete your request.
Please contact the server administrator at email@example.com to inform them of the time this error occurred, and the actions you performed just before this error.
More information about this error may be available in the server error log."