I installed JRuby 1.3.0 but when I tried to run “gem” I got the following error message:

C:\ruby\jruby-1.3.0\bin>jruby gem install rails
C:/ruby/jruby-1.3.0/bin/../lib/ruby/site_ruby/1.8/rubygems.rb:881:in `searcher’: Mutex relocking by same thread (ThreadError)
from C:/ruby/jruby-1.3.0/bin/../lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:33:in `require’
from C:/ruby/jruby-1.3.0/bin/../lib/ruby/site_ruby/1.8/rubygems.rb:499:in `ensure_gem_subdirectories’
from C:/ruby/jruby-1.3.0/bin/../lib/ruby/site_ruby/1.8/rubygems/defaults/jruby.rb:12:in `ensure_gem_subdirectories’
from C:/ruby/jruby-1.3.0/bin/../lib/ruby/site_ruby/1.8/rubygems.rb:892:in `set_home’
from C:/ruby/jruby-1.3.0/bin/../lib/ruby/site_ruby/1.8/rubygems.rb:467:in `dir’
from C:/ruby/jruby-1.3.0/bin/../lib/ruby/site_ruby/1.8/rubygems.rb:910:in `set_paths’
from C:/ruby/jruby-1.3.0/bin/../lib/ruby/site_ruby/1.8/rubygems/defaults/jruby.rb:17:in `set_paths’
from C:/ruby/jruby-1.3.0/bin/../lib/ruby/site_ruby/1.8/rubygems.rb:689:in `path’
… 8 levels…
from C:/ruby/jruby-1.3.0/bin/../lib/ruby/site_ruby/1.8/rubygems.rb:1125
from C:/ruby/jruby-1.3.0/bin/../lib/ruby/site_ruby/1.8/rubygems.rb:8:in `require’
from gem:8

C:\ruby\jruby-1.3.0\bin>jirb.bat
C:\ruby\jruby-1.3.0\bin\jirb:16:in `require’: no such file to load — irb (LoadError)
from C:\ruby\jruby-1.3.0\bin\jirb:16

Windows XP X86_64 SP2

C:\ruby\jruby-1.2.0\bin>java -version
java version “1.6.0_14”
Java(TM) SE Runtime Environment (build 1.6.0_14-b08)
Java HotSpot(TM) 64-Bit Server VM (build 14.0-b16, mixed mode)