There's typo in ebuild part enabling OSS sound support (introduced by me) and broken phonon in IUSE (this one is not my fault :P). I've tried to enable phonon properly, but it seems that phonon plugin core is broken currently (some runtime initialization), hence I decided to remove phonon support completely for now.
Created attachment 200515 [details, diff] Patch fixing mentioned issues - should be done with revbump in this case
+*kadu-0.6.5.2-r3 (11 Aug 2009) + + 11 Aug 2009; Tomáš Chvátal <scarabeus@gentoo.org> + -kadu-0.6.5.2-r2.ebuild, +kadu-0.6.5.2-r3.ebuild: + Fix OSS useflag per bug #280664 (revbumped for that). Proxy commit for + reavertm. Done :]