Install a gem gives: Unhandled special

since this only concerns the documentation, is this message concerning?

[email protected]:~#
[email protected]:~# gem install feedtools

FeedTool’s caching schema has changed to allow Feed objects to be
serialized to the cache. This should offer some limited speed up
in some cases.

Successfully installed uuidtools-2.0.0
Successfully installed builder-2.1.2
Successfully installed feedtools-0.2.29
3 gems installed
Installing ri documentation for uuidtools-2.0.0…
Installing ri documentation for builder-2.1.2…
ERROR: While generating documentation for builder-2.1.2
… MESSAGE: Unhandled special: Special: type=17, text=""
… RDOC args: --ri --op /var/lib/gems/1.8/doc/builder-2.1.2/ri --title
Builder – Easy XML Building --main README --line-numbers --quiet lib
CHANGES Rakefile README doc/releases/builder-1.2.4.rdoc doc/releases/
builder-2.0.0.rdoc doc/releases/builder-2.1.1.rdoc
(continuing with the rest of the installation)
Installing ri documentation for feedtools-0.2.29…
Installing RDoc documentation for uuidtools-2.0.0…
Installing RDoc documentation for builder-2.1.2…
Installing RDoc documentation for feedtools-0.2.29…
[email protected]:~#