Rails deployment

Hello, I want to deploy my RoR application on a apache tomcat server. I found a workthrough at http://www.digitalsanctum.com/2007/07/24/jruby-deploying-a-rails-application-on-tomcat/ but I have problems with the goldspike plugin. When I try to execute "rake war:standalone:create" I always get the error:

** Invoke war:standalone:create (first_time) ** Invoke war:init (first_time) ** Invoke environment (first_time) ** Execute environment ** Execute war:init ** Execute war:standalone:create info: Assembling web application info: Packing needed Java libraries ... info: Packing needed Ruby gems ... info: Packing needed files ... info: Creating web archive rake aborted! Error: failed to create archive, error code ../vendor/plugins/goldspike/lib/packer.rb:56:in `jar' ../vendor/plugins/goldspike/lib/packer.rb:190:in `create_war' ../vendor/plugins/goldspike/lib/create_war.rb:64:in `create_war' ../vendor/plugins/goldspike/lib/create_war.rb:47:in `create_war_file' ../vendor/plugins/goldspike/tasks/war.rake:24 C:/ruby/lib/ruby/gems/1.8/gems/rake-0.7.2/lib/rake.rb:399:in `call' C:/ruby/lib/ruby/gems/1.8/gems/rake-0.7.2/lib/rake.rb:399:in `execute' C:/ruby/lib/ruby/gems/1.8/gems/rake-0.7.2/lib/rake.rb:399:in `each' C:/ruby/lib/ruby/gems/1.8/gems/rake-0.7.2/lib/rake.rb:399:in `execute' C:/ruby/lib/ruby/gems/1.8/gems/rake-0.7.2/lib/rake.rb:369:in `invoke' C:/ruby/lib/ruby/gems/1.8/gems/rake-0.7.2/lib/rake.rb:362:in `synchronize' C:/ruby/lib/ruby/gems/1.8/gems/rake-0.7.2/lib/rake.rb:362:in `invoke' C:/ruby/lib/ruby/gems/1.8/gems/rake-0.7.2/lib/rake.rb:1935:in `run' C:/ruby/lib/ruby/gems/1.8/gems/rake-0.7.2/lib/rake.rb:1935:in `each' C:/ruby/lib/ruby/gems/1.8/gems/rake-0.7.2/lib/rake.rb:1935:in `run' C:/ruby/lib/ruby/gems/1.8/gems/rake-0.7.2/bin/rake:7 C:\ruby\bin\rake:16:in `load' C:\ruby\bin\rake:16 -e:3:in `load' -e:3

has anyone an idea what that could be or how I can resolve this? I get this error for all my projects, also fo projects which are created fresh...

Thanks in advance Manfred