Can't install gem by rbenv_gem resource

[ironsand]

I tried to install moji gem by this code:

rbenv_gem "moji" do
  ruby_version "2.0.0-p451"
end

If the gem is already installed, there were no error.

I uninstalled the moji gem directly by server and run the cookbook again, then got this error:

---- Begin output of /usr/local/rbenv/versions/2.0.0-p451/bin/gem install moji -q --no-rdoc --no-ri  -v "1.6"  ----
STDOUT: 
STDERR: ERROR:  While executing gem ... (Errno::ENOENT)
    No such file or directory - /root/.gem/ruby/2.0.0/cache/moji-1.6.gem
---- End output of /usr/local/rbenv/versions/2.0.0-p451/bin/gem install moji -q --no-rdoc --no-ri  -v "1.6"  ----

I'm using /usr/local for install_prefx.
All gem files are in a directory /usr/local/rbenv/versions/2.0.0-p451/lib/ruby/gems/2.0.0/cache/ .

How can I install gems by rbenv_gem resource?
Am I doing something wrong?