diff --git a/bin/sim_launcher b/bin/sim_launcher
old mode 100644
new mode 100755
diff --git a/lib/sim_launcher/simulator.rb b/lib/sim_launcher/simulator.rb
index 543ecb9..ccbe151 100644
--- a/lib/sim_launcher/simulator.rb
+++ b/lib/sim_launcher/simulator.rb
@@ -105,7 +105,7 @@ def iphonesim_path
       return $1
     end
 
-    raise "Didn't find ios-sim in your $PATH. Please install, e.g. using\n\n\tbrew install ios-sim"
+    raise "Didn't find the ios-sim binary in your $PATH.\n\nPlease install, e.g. using Homebrew:\n\tbrew install ios-sim\n\n"
   end
 end
 end
diff --git a/sim_launcher.gemspec b/sim_launcher.gemspec
index 13650e9..1eb21b9 100644
--- a/sim_launcher.gemspec
+++ b/sim_launcher.gemspec
@@ -16,5 +16,16 @@ Gem::Specification.new do |s|
   s.executables   = `git ls-files -- bin/*`.split("\n").map{ |f| File.basename(f) }
   s.require_paths = ["lib"]
 
+  s.post_install_message = <<-EOS
+
+  ****************************************************************************************
+  * sim_launcher expects the ios-sim binary in your $PATH. Install using e.g. Homebrew:  *
+  *                                                                                      *
+  *     brew install ios-sim                                                             *
+  *                                                                                      *
+  ****************************************************************************************
+
+  EOS
+
   s.add_dependency "sinatra"
 end