The problem was with plugin “DB Cache Reloaded Fix”. When I disabled it, Q&A work fine.
I have another problem yet.
When new user can ask question, he have to fill the register form. But… when he click confirm button, account is registered, but the question is not added. The user remains on the page to ask questions (with blank forms), there is no error message and do not know what happened.
OK… Isn’t acctual. I has problem with jquery version loaded with my theme.
