For YouTube, there's YTD Downloader (Google it to get the link). It also works with quite a few other sites.
For XTube, there's XTube Video Downloader. Real Downloader always seems to have problems with XTube, at least in Windows.
I'm a Chrome user and both of these work flawlessly every time. They also download faster than the Real Downloader default speed, which is GLACIAL. Real wants you to pay for an upgrade to get faster download speeds. That's plain stingy. I really don't like the company in general. Their video file format (.rm) never really caught on, it doesn't convert well to other formats, and they don't really seem to offer anything else worth paying for. Just my opinion.