Mmmh... are you using the 2010-10-10 CCCP? Asking just to be safe, perhaps you're on an older version, though that should hardly be the problem.
Anyway, with subtitles, you'll want to make sure that it's using directvobsud properly, which it should with default settings. Have you trying resetting to the defaults in the meantime?
Another thing you can do is look for the green arrow icon while you play videos. Right click that, and then it should be intuitive how to proceed ─ that is assuming that it's using directvobsub as it shoud, of course.
I guess these are the couple things to try/questions to reply before searching elsewhere for where the issue might reside.