Uploadify authentication problem

I'm trying to use Uploadify in my project. Everything works in my
machine, locally. The problem is when I use the same code in my
production environment.
When I try to upload a photo, it returns an error "HTTP 401", but there
are no errors in the log.

Rails(2.3.5)
Uploadify(2.1.0)

Here is my FlashSessionCookieMiddleware where the problem with the Flash
authentication shoud be solved.