Could not read gem at /Library/Ruby/Gems/2.0.0/ruby/2.0.0/cache/will_paginate-3.0.7.gem

Bundle Install 提示如下：

Bundler::GemspecError: Could not read gem at /Library/Ruby/Gems/2.0.0/ruby/2.0.0/cache/will_paginate-3.0.7.gem. It may be corrupted.
An error occurred while installing will_paginate (3.0.7), and Bundler
cannot continue.
Make sure that gem install will_paginate -v '3.0.7' succeeds before
bundling.

可是 will_paginate -v '3.0.7' 确认安装成功

前往 /Library/Ruby/Gems/2.0.0/ruby/2.0.0/cache/ 文件夹 ， will_paginate 已经存在

请解答？