проблема при установке gem

Я пытаюсь установить '''sudo gem install soap4r'''

Но столкнулся с проблемой ниже..

Successfully installed httpclient-2.2.4

Successfully installed soap4r-1.5.8

2 gems installed

Installing ri documentation for httpclient-2.2.4...


RDoc failure in lib/httpclient.rb at or around line 405 column 16

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:

ERROR:  While executing gem ... (NoMethodError)
    undefined method `name' for #<RubyToken::TkLPAREN:0xb6598024>