YoVille will NEVER ask for your password, so please be wary of malicious emails and/or forum posts that request your password, including via web links.
There were a few houses released with rooms that don't have any arrow to link to the room. There isn't any way to get into it unless you can find the rooms code name. I'm not sure if those have been released.
I was going through some of my old houses and noticed this too. Do the Viking have a reply to this? Do we need to submit a ticket to get access to this room? Does it not really exist? Either way, it would be nice if it was fixed.