My theory now is that those are not errors, even though they are written to xerrs.log, unless that makes them errors by definition Yes, we do want to get rid of them. I think they are information from mplayer that the frontend can use, for instance, as gnome-mplayer does to report on the percentage of cache fill.I get no errors in xerrs.log if I use gnome-mplayer in pupradio.
One can see in the mplayer command line above that gnome-mplayer send the -quiet option, but that is still more info than we want.