[Radiant] AttachmentFu::Backends error when installing page_attachments extension

[Oli]

Hi All,

Does anyone have troubleshooting advice for attachment_fu backend
being uninitialized? I've installed the mini_magick 1.2.3 gem and
checked out trunk attachment_fu into vendor/plugins as per the wiki
article (well, I installed page_attachments first, then
attachment_fu/mini_magick after getting the 'no technoweenie' error
:-). However:

    $ rake db:migrate:extensions

keeps failing with:

    $ uninitialized constant Technoweenie::AttachmentFu::Backends
    $ vendor/plugins/attachment_fu/lib/technoweenie/attachment_fu.rb:77:in
`has_attachment'

that line reads:

    storage_mod =
Technoweenie::AttachmentFu::Backends.const_get("#{options[:storage].to_s.classify}Backend")

/usr/local/lib/ruby/gems/1.8/gems is in my path, and is set as
gem_root. Radiant is installed by gem and should be 0.6.6 (although in
the --trace the paths all seem to be 0.6.4)

Any advice would be much appreciated. TIA

peace - oli