Error while running a program with rubygame


I try to install rubygame on my mac to use it in a project. I got no
errors at the installation, but when I run the program (which only
contains '‘require ‘ruby game’’), I have this error :

dyld: Library not loaded:
Referenced from: /usr/local/bin/rsdl
Reason: image not found
Trace/BPT trap: 5

Any ideas to fix this ?

Thank you in advance,