Rails invent me something

Hi, i’m french sorry for my english.

I have a little with Rails, he say me somethings is not related and i
have a bug.

This is my forum controller: http://pastebin.com/0xaN6st4
My _form.html.erb: http://pastebin.com/KUQL4mtD
My routes: http://pastebin.com/j03wR1t3

A screen of my rake routes:

And a screen of the error…

I don’t know where is found foras ? WHAT THE FUCK ?

Thanks you