64bit linux -- can't play anything

[Shonumi]

You haven't said which Linux distro you're using, but my gut instinct is to get rid of any running instance of xdg-screensaver (using killall). If you don't use screensavers, you may want to find out where xdg-screensaver is being run in the first place and disable it altogether. FYI, everything else out the standard output you posted is pretty normal, up until Dolphin aborts that is.