Unable to fix permissions
If you have access to other Mac, you can boot yours in target mode. Attach it to the other system. It should show up as an external drive on the other system. From there, you can either fix the permission, or reload your operating system.

If you don't have access to another computer, you may want to ask around for a USB drive that has a system installed. (Friends, family, Apple store, Ebay, etc).