Template is missing, latest edge

hi everyone,
I have a project that is using a good snapshot of edge, however I
tried some latest rails builds and I got some weird errors.

when using a respond_to block in a controller, rails isn't able to
find the related view.
this is a pastie, with a backtrace and controller code: http://pastie.org/474696
(please note that I'm using a namespaced controller here).

I would really like to understand what's going on.