Hmm - i reported for the package compositing. So when compositing does not work i see it as a grave problem for this package.
No, you filed the bug against the "composite" package, which is a "Live performance sequencer", see <http://packages.debian.org/sid/composite>.
If you want to file a bug against the non-working composite feature of your window manager, please figure out which package provides this in the first place (in your case "kde-window-manager", which is where Alessio reassigned this bug to).
Furthermore, I doubt your name is really "Debian", so please get your reportbug configured to show your real name correctly.
Best Regards, Fabian