Unknown substitution variable $(PROJECT_NAME)

[ArloL]

My PRODUCT_NAME is set to $(PROJECT_NAME). I get an error when trying to call clean:

$ bundle exec rake --trace clean
** Invoke clean (first_time)
** Invoke remove_build_dir (first_time)
** Execute remove_build_dir
rm -rf build
** Invoke ios:clean (first_time)
** Invoke init (first_time)
** Execute init
** Invoke remove_build_dir 
** Invoke load_project (first_time)
** Execute load_project
** Execute ios:clean
rake aborted!
Unknown substitution variable $(PROJECT_NAME)
/Users/ArloLOK/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/xcoder-0.1.18/lib/xcode/configuration.rb:446:in `block in substitute'
/Users/ArloLOK/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/xcoder-0.1.18/lib/xcode/configuration.rb:441:in `gsub'
/Users/ArloLOK/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/xcoder-0.1.18/lib/xcode/configuration.rb:441:in `substitute'
/Users/ArloLOK/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/xcoder-0.1.18/lib/xcode/configuration.rb:98:in `block in property'
/Users/ArloLOK/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/xcoder-0.1.18/lib/xcode/configuration.rb:96:in `block in property'
/Users/ArloLOK/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/xcoder-0.1.18/lib/xcode/builder/base_builder.rb:282:in `product_name'
/Users/ArloLOK/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/xcoder-0.1.18/lib/xcode/builder/base_builder.rb:233:in `clean'
/Users/ArloLOK/Developer/CocoaLumberjackFramework/Rakefile:64:in `block (2 levels) in <top (required)>'
/Users/ArloLOK/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/rake-10.1.0/lib/rake/task.rb:236:in `call'
/Users/ArloLOK/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/rake-10.1.0/lib/rake/task.rb:236:in `block in execute'
/Users/ArloLOK/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/rake-10.1.0/lib/rake/task.rb:231:in `each'
/Users/ArloLOK/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/rake-10.1.0/lib/rake/task.rb:231:in `execute'
/Users/ArloLOK/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/rake-10.1.0/lib/rake/task.rb:175:in `block in invoke_with_call_chain'
/Users/ArloLOK/.rbenv/versions/1.9.3-p327/lib/ruby/1.9.1/monitor.rb:211:in `mon_synchronize'
/Users/ArloLOK/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/rake-10.1.0/lib/rake/task.rb:168:in `invoke_with_call_chain'
/Users/ArloLOK/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/rake-10.1.0/lib/rake/task.rb:197:in `block in invoke_prerequisites'
/Users/ArloLOK/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/rake-10.1.0/lib/rake/task.rb:195:in `each'
/Users/ArloLOK/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/rake-10.1.0/lib/rake/task.rb:195:in `invoke_prerequisites'
/Users/ArloLOK/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/rake-10.1.0/lib/rake/task.rb:174:in `block in invoke_with_call_chain'
/Users/ArloLOK/.rbenv/versions/1.9.3-p327/lib/ruby/1.9.1/monitor.rb:211:in `mon_synchronize'
/Users/ArloLOK/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/rake-10.1.0/lib/rake/task.rb:168:in `invoke_with_call_chain'
/Users/ArloLOK/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/rake-10.1.0/lib/rake/task.rb:161:in `invoke'
/Users/ArloLOK/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/rake-10.1.0/lib/rake/application.rb:149:in `invoke_task'
/Users/ArloLOK/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/rake-10.1.0/lib/rake/application.rb:106:in `block (2 levels) in top_level'
/Users/ArloLOK/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/rake-10.1.0/lib/rake/application.rb:106:in `each'
/Users/ArloLOK/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/rake-10.1.0/lib/rake/application.rb:106:in `block in top_level'
/Users/ArloLOK/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/rake-10.1.0/lib/rake/application.rb:115:in `run_with_threads'
/Users/ArloLOK/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/rake-10.1.0/lib/rake/application.rb:100:in `top_level'
/Users/ArloLOK/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/rake-10.1.0/lib/rake/application.rb:78:in `block in run'
/Users/ArloLOK/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/rake-10.1.0/lib/rake/application.rb:165:in `standard_exception_handling'
/Users/ArloLOK/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/rake-10.1.0/lib/rake/application.rb:75:in `run'
/Users/ArloLOK/.rbenv/versions/1.9.3-p327/lib/ruby/gems/1.9.1/gems/rake-10.1.0/bin/rake:33:in `<top (required)>'
/Users/ArloLOK/.rbenv/versions/1.9.3-p327/bin/rake:23:in `load'
/Users/ArloLOK/.rbenv/versions/1.9.3-p327/bin/rake:23:in `<main>'
Tasks: TOP => clean => ios:clean

Everything works fine when I don't use $(PROJECT_NAME) or with 0.1.15.