This is one aspect of linux that really annoys me. Everything is set up correctly and working one week, and the next things stop working for no apparent reason.
I think that if you change the word 'linux' to 'computers, you'll be nearer the mark :-)
I've seen wierd things like this on windows, macs and linux-based OS's over the years. I share your pain :-) More seriously - computer systems are often seriously frustrating things.
They are very complex systems designed by human beings - no wonder they don't always behave as expected!
In your case, for example, the problem is unlikely to be with linux (the kernel) but could be with realplayer, the BBC website, KDE, the browser or browsers you are trying, the way that the particular distro you are using is configured - there are an awful lot of variables involved here.
Let us know the distro you're using then someone can advise how to install ldconfig. I'd never heard of it before but it seems to be installed on my mandrkae 9.2 system.
Post the URl of a page that used to work and no longer does so and we can try and figure out what may have happened.
Syd