diff --git a/Library/Homebrew/formula.rb b/Library/Homebrew/formula.rb
index 453c1082f8..2ba8f57622 100644
--- a/Library/Homebrew/formula.rb
+++ b/Library/Homebrew/formula.rb
@@ -448,6 +448,7 @@ protected
         rd.close
         $stdout.reopen wr
         $stderr.reopen wr
+        args.collect!{|arg| arg.to_s}
         exec(cmd, *args) rescue nil
         exit! 1 # never gets here unless exec threw or failed
       end