Looks like you have space in your application path.
/Users/Darek/Dropbox private/Dropbox/Programowanie/Ruby on Rails/test/storemanager/
Kindly rename and remove spaces from your Ruby on Rails folder and try to build application once again.
Probably not a great idea to build your project in your Dropbox directory!
The *least* problematic thing that will happen is a whole lot of unnecessary network traffic copying intermediate build files to Dropbox. And that's a lot of files!
Lol, i don't understand how such advanced tool can't read path with spaces. The same problem have Matlab. It's so stupid, but ok, somehow I'll manage to live with it. Thaks for help .
Ok, in dropbox it's not good idea but when i stop sync, it's ok. Sometimes it's not a problem, sometimes sync it's too long. In that case i turn it off and works on . The good it's that i take my laptop and works on it without remember about copy . Of course i can flag build folder in dropbox to not sync .