On reflection, I think the lucid 5.2.5 ffmpeg is 0.6-2 from Maverick--that is, the libraries are from medibuntu for Maverick.Lucid 525 Mplayer package
Thanks for checking gnome-mplayer 1.0.4 pemasu. I will fix it now. That's done. I have got to remember to check the menu entry and jwm.