From Instant Rails 2.0 to Rails 2.1.0 - cache problem

i'm trying to update to rails 2.1 using instant rails, so i can use
new cache features, but when i try to use the method
in my controller, i get the message

"undefined method `cache' for Rails:Module (NoMethodError)"

and if i try to set the cache store
("ActionController::Base.cache_store = :memory_store")
in a conf file, i get: "undefined method `cache_store=' for
ActionController::Base:Class (NoMethodError)"

the version message for ("rails -v") is "Rails 2.1.0", so i assume
the version is ok. does anyone know what could be the problem? thanks.

double post, please ignore (or delete). i posted
it hours ago through google groups and only now
it appeared. i'll post here directly next time.

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