This is due to not having at least "hoe" and maybe "rubyforge" gems not also updated.
Just do a global update if you don't have any others, but otherwise just try going into irb and directly including the memcache-client lib.
# irb
require 'rubygems' gem 'memcache-client'
You should get an error here about what's missing.
Nathaniel.
Krates Ng wrote: