Debugger Issues

When I attempt to run the debugger, I receive the following :

Cannot connect to the debugged process at port 50672 in 10s:

Error Output:
/Users/aaaa/.rvm/gems/ruby-1.9.2-p180@rails3/bundler/gems/xxxx-9a3e7efe7306/xxxx.gemspec:37:in ``': No such file or directory - git ls-files (Errno::ENOENT)
    from /Users/aaaa/.rvm/gems/ruby-1.9.2-p180@rails3/bundler/gems/xxxx-9a3e7efe7306/xxxx.gemspec:37:in `block in <main>'
    from /Users/aaaa/.rvm/rubies/ruby-1.9.2-p180/lib/ruby/site_ruby/1.9.1/rubygems/specification.rb:426:in `initialize'
......



Looking at line 37 of that gem spec, I see the following :

  s.files         = `git ls-files`.split("\n")   # <-- Line 37
  s.test_files    = `git ls-files -- {test,spec,features}/*`.split("\n")
  s.executables   = `git ls-files -- bin/*`.split("\n").map{ |f| File.basename(f) }

This particular gemfile that its complaining about is referenced in my Gemfile as such :

gem 'xxxx', :git => 'git@github.com:company/xxxx.git', :require =>['xxxx', 'xxxx_rails']

Any insight is greatly appreciated.