Well I don't use KDE so I'm not much help w/ that problem. I like Roxfiler myself. Works very good. But as for the DVD issue- you don't need to mount it to watch a movie. Look at the configuration for Xine. It (like most Linux apps) expects to find your dvd drive as /dev/dvd BUT there is no such thing! So....you need to create it if it doesn't already exist.

My dvd drive is the Primary Slave so it's called /dev/hdb. I just do this:

ln -s /dev/hdb /dev/dvd

Now, if you try to use /dev/dvd you're really using /dev/hdb. Make sense?

Of course you can configure Xine to use /dev/hdb if you don't want to mess about w/ symlinks although symlinks really are easy and it would be to your advantage to use them.