I wrote a gem for a package called "tree", version 0.0.0.  I built a
gemfile and installed it.  Now the code is installed and works, but
only some of the gem utitlities know that it's there.  I suspect I did
something wrong in my gem specification file, but I can't figure out
what.

Does anyone have any ideas what is wrong or suggestions on how to
debug?

Here are the specifics of the problem: "gem list" and "gemwhich" find
my gem

$ gem list

*** LOCAL GEMS ***

rake (0.6.2)
    Ruby based make-like utility.

rubygems-update (0.8.11)
    RubyGems Update GEM

sources (0.0.1)
    This package provides download sources for remote gem installation

tree (0.0.0)
    Tree is an ordered n-ary branching tree structure

$ gemwhich tree
/homes/billmcn/lib/ruby/gems/1.8/gems/tree-0.0.0/lib/tree.rb

but 'gem specification' and 'gem uninstall' do not work

$ gem specification tree
ERROR:  Unknown gem tree

$ gem uninstall tree
Attempting to uninstall gem 'tree'
ERROR:  While executing gem ... (RuntimeError)
    Unknown RubyGem: tree (> 0)

These commands work for other gems installed on my machine.

When I go look under /homes/billmcn/lib/ruby/gems/1.8 there appear to
be the appropriate cache, doc, gems, and specifications files and
subdirectories.  In particular, here is the specfile

$ cat tree-0.0.0.gemspec
Gem::Specification.new do |s|
  s.name = %q{tree}
  s.version = "0.0.0"
  s.date = %q{2005-12-01}
  s.summary = %q{Tree is an ordered n-ary branching tree structure}
  s.email = %q{billmcn / u.washington.edu}
  s.homepage = %q{http://www.washington.edu/~billmcn}
  s.description = %q{This module implement order n-ary branching tree
structures.  It includes support for breadth- and depth- first
iteration, and serialization to and from a bracketed tree string.}
  s.has_rdoc = true
  s.authors = ["W.P. McNeill"]
  s.files = ["test/test_tree.rb", "lib/tree.rb", "README"]
  s.test_files = ["test/test_tree.rb"]
  s.rdoc_options = ["--title", "Tree -- Ruby Tree", "--main", "README",
"--line-numbers", "--inline-source"]
  s.extra_rdoc_files = ["README"]
end


This is RedHat Linux.  Ruby version

$ ruby -v
ruby 1.8.3 (2005-09-21) [i686-linux]

Note that I don't have write permissions to /usr so this version of
Ruby is installed in my home directory.

RUBYOPT=rubygems is set.  Here is my gems environment

$ gem env
Rubygems Environment:
  - VERSION: 0.8.11 (0.8.11)
  - INSTALLATION DIRECTORY: /homes/billmcn/lib/ruby/gems/1.8
  - GEM PATH:
     - /homes/billmcn/lib/ruby/gems/1.8
  - REMOTE SOURCES:
     - http://gems.rubyforge.org


Thanks for any suggestions you have.