It's usually some method called on a very large negative Fixnum. Note below how different install runs produce different errors. (Who said that computers were deterministic?) [sliver:~/Desktop] gkistner$ sudo gem install facets Successfully installed facets-1.7.46 Installing ri documentation for facets-1.7.46... ERROR: While executing gem ... (NoMethodError) undefined method `empty?' for -517611318:Fixnum [sliver:~/Desktop] gkistner$ sudo gem uninstall facets Successfully uninstalled facets version 1.7.46 [sliver:~/Desktop] gkistner$ sudo gem install facets --backtrace ERROR: While executing gem ... (NoMethodError) undefined method `shift' for -517611318:Fixnum /usr/local/lib/ruby/site_ruby/1.8/rubygems/package.rb:87:in `new_from_stream' /usr/local/lib/ruby/site_ruby/1.8/rubygems/package.rb:441:in `each_entry' /usr/local/lib/ruby/site_ruby/1.8/rubygems/package.rb:439:in `loop' /usr/local/lib/ruby/site_ruby/1.8/rubygems/package.rb:439:in `each_entry' /usr/local/lib/ruby/site_ruby/1.8/rubygems/package.rb:424:in `each' /usr/local/lib/ruby/site_ruby/1.8/rubygems/package.rb:591:in `each' /usr/local/lib/ruby/site_ruby/1.8/rubygems/package.rb:411:in `new' /usr/local/lib/ruby/site_ruby/1.8/rubygems/package.rb:590:in `each' /usr/local/lib/ruby/site_ruby/1.8/rubygems/package.rb:445:in `each_entry' /usr/local/lib/ruby/site_ruby/1.8/rubygems/package.rb:439:in `loop' /usr/local/lib/ruby/site_ruby/1.8/rubygems/package.rb:439:in `each_entry' /usr/local/lib/ruby/site_ruby/1.8/rubygems/package.rb:424:in `each' /usr/local/lib/ruby/site_ruby/1.8/rubygems/package.rb:586:in `each' /usr/local/lib/ruby/site_ruby/1.8/rubygems/format.rb:62:in `from_io' /usr/local/lib/ruby/site_ruby/1.8/rubygems/package.rb:579:in `open_from_io' /usr/local/lib/ruby/site_ruby/1.8/rubygems/package.rb:801:in `open_from_io' /usr/local/lib/ruby/site_ruby/1.8/rubygems/format.rb:59:in `from_io' /usr/local/lib/ruby/site_ruby/1.8/rubygems/format.rb:47:in `from_file_by_path' /usr/local/lib/ruby/site_ruby/1.8/rubygems/installer.rb:62:in `install' /usr/local/lib/ruby/site_ruby/1.8/rubygems/remote_installer.rb:444:in `install' /usr/local/lib/ruby/site_ruby/1.8/rubygems/gem_commands.rb:258:in `execute' /usr/local/lib/ruby/site_ruby/1.8/rubygems/gem_commands.rb:220:in `each' /usr/local/lib/ruby/site_ruby/1.8/rubygems/gem_commands.rb:220:in `execute' /usr/local/lib/ruby/site_ruby/1.8/rubygems/command.rb:69:in `invoke' /usr/local/lib/ruby/site_ruby/1.8/rubygems/cmd_manager.rb:117:in `process_args' /usr/local/lib/ruby/site_ruby/1.8/rubygems/cmd_manager.rb:88:in `run' /usr/local/lib/ruby/site_ruby/1.8/rubygems/gem_runner.rb:29:in `run' /usr/local/bin/gem:23 [sliver:~/Desktop] gkistner$ sudo gem uninstall facets ERROR: While executing gem ... (RuntimeError) Unknown RubyGem: facets (> 0) [sliver:~/Desktop] gkistner$ sudo gem install facets --backtrace Successfully installed facets-1.7.46 Installing ri documentation for facets-1.7.46... RDoc failure in lib/facets/more/cookie.rb at or around line 336 column -517618807 Before reporting this, could you check that the file you're documenting compiles cleanly--RDoc is not a full Ruby parser, and gets confused easily if fed invalid programs. The internal error was: While generating documentation for facets-1.7.46 ... MESSAGE: unget past beginning of file ... RDOC args: --ri --op /usr/local/lib/ruby/gems/1.8/doc/facets-1.7.46/ri --quiet lib /usr/local/lib/ruby/1.8/rdoc/parsers/parse_rb.rb:395:in `ungetc' /usr/local/lib/ruby/1.8/rdoc/parsers/parse_rb.rb:508:in `ungetc' /usr/local/lib/ruby/1.8/irb/slex.rb:234:in `match_io' /usr/local/lib/ruby/1.8/irb/slex.rb:222:in `match_io' (continuing with the rest of the installation) Installing RDoc documentation for facets-1.7.46... ERROR: While executing gem ... (NoMethodError) undefined method `postproc' for -517611318:Fixnum /usr/local/lib/ruby/1.8/irb/slex.rb:135:in `create_subnode' /usr/local/lib/ruby/1.8/irb/slex.rb:147:in `create_subnode' /usr/local/lib/ruby/1.8/irb/slex.rb:67:in `create' /usr/local/lib/ruby/1.8/irb/slex.rb:39:in `def_rule' /usr/local/lib/ruby/1.8/irb/slex.rb:47:in `def_rules' /usr/local/lib/ruby/1.8/irb/slex.rb:46:in `each' /usr/local/lib/ruby/1.8/irb/slex.rb:46:in `def_rules' /usr/local/lib/ruby/1.8/rdoc/parsers/parse_rb.rb:714:in `lex_init' /usr/local/lib/ruby/1.8/rdoc/parsers/parse_rb.rb:448:in `initialize' /usr/local/lib/ruby/1.8/rdoc/parsers/parse_rb.rb:1393:in `new' /usr/local/lib/ruby/1.8/rdoc/parsers/parse_rb.rb:1393:in `initialize' /usr/local/lib/ruby/1.8/rdoc/parsers/parserfactory.rb:96:in `new' /usr/local/lib/ruby/1.8/rdoc/parsers/parserfactory.rb:96:in `parser_for' /usr/local/lib/ruby/1.8/rdoc/rdoc.rb:209:in `parse_files' /usr/local/lib/ruby/1.8/rdoc/rdoc.rb:203:in `each' /usr/local/lib/ruby/1.8/rdoc/rdoc.rb:203:in `parse_files' /usr/local/lib/ruby/1.8/rdoc/rdoc.rb:246:in `document' /usr/local/lib/ruby/site_ruby/1.8/rubygems/doc_manager.rb:101:in `run_rdoc' /usr/local/lib/ruby/site_ruby/1.8/rubygems/doc_manager.rb:80:in `install_rdoc' /usr/local/lib/ruby/site_ruby/1.8/rubygems/doc_manager.rb:58:in `generate_rdoc' /usr/local/lib/ruby/site_ruby/1.8/rubygems/gem_commands.rb:289:in `execute' /usr/local/lib/ruby/site_ruby/1.8/rubygems/gem_commands.rb:288:in `each' /usr/local/lib/ruby/site_ruby/1.8/rubygems/gem_commands.rb:288:in `execute' /usr/local/lib/ruby/site_ruby/1.8/rubygems/gem_commands.rb:220:in `each' /usr/local/lib/ruby/site_ruby/1.8/rubygems/gem_commands.rb:220:in `execute' /usr/local/lib/ruby/site_ruby/1.8/rubygems/command.rb:69:in `invoke' /usr/local/lib/ruby/site_ruby/1.8/rubygems/cmd_manager.rb:117:in `process_args' /usr/local/lib/ruby/site_ruby/1.8/rubygems/cmd_manager.rb:88:in `run' /usr/local/lib/ruby/site_ruby/1.8/rubygems/gem_runner.rb:29:in `run' /usr/local/bin/gem:23