This appears to be a duplicate of a known bug. If you do not require xemacs21, maybe you can just silently uninstall it. tuareg-mode appears to prefer xemacs21-nomule over other emacsen, which is probably a mistake (I filed bug #638781 about this issue just now). You apparently already have emacs23 so if you are fine with that, you can ignore the problem with xemacs21.
This appears to be a duplicate of a known bug. If you do not require xemacs21, maybe you can just silently uninstall it. tuareg-mode appears to prefer xemacs21-nomule over other emacsen, which is probably a mistake (I filed bug #638781 about this issue just now). You apparently already have emacs23 so if you are fine with that, you can ignore the problem with xemacs21.