Error installing gem

Hi, I am getting the following error while installing the gems.. /usr/local/lib/site_ruby/1.8/rubygems.rb:272:in `initialize': wrong number of arguments (1 for 0) (ArgumentError)

root@raju-laptop:/home/raju/workspace# sudo gem update --system /usr/local/lib/site_ruby/1.8/rubygems.rb:272:in `initialize': wrong number of arguments (1 for 0) (ArgumentError)         from /usr/local/lib/site_ruby/1.8/rubygems.rb:272:in `new'         from /usr/local/lib/site_ruby/1.8/rubygems.rb:272:in `configuration'         from /usr/local/lib/site_ruby/1.8/rubygems.rb:512:in `path'         from /usr/local/lib/site_ruby/1.8/rubygems/source_index.rb:66:in `installed_spec_directories'         from /usr/local/lib/site_ruby/1.8/rubygems/source_index.rb:56:in `from_installed_gems'         from /usr/local/lib/site_ruby/1.8/rubygems.rb:726:in `source_index'         from /usr/local/lib/site_ruby/1.8/rubygems/gem_path_searcher.rb:86:in `init_gemspecs'         from /usr/local/lib/site_ruby/1.8/rubygems/gem_path_searcher.rb:21:in `initialize'          ... 6 levels...         from /usr/local/lib/site_ruby/1.8/rubygems/gem_runner.rb:8:in `require'         from /usr/local/lib/site_ruby/1.8/rubygems/gem_runner.rb:8         from /usr/bin/gem:8:in `require'         from /usr/bin/gem:8

thanks & regards Raju K ARalikatti