The apostrophe in “can’t” needs to be escaped… if I’m reading this right.
@Roma
Your host should have it turned on in Apache. I don’t believe Multiviews is any potential security risk. At least not that I can find.
@6
Your example URL is down… is there anywhere else?
I’d imagine not anytime soon. PHPBB3 is totally bloated… I can think of easier ways though…