In http://www.winehq.org/pipermail/wine-devel/2009-August/077858.html Hin-Tak wrote
... The last part (missing charset) seems to be some harmless thing winetrick does - instead of gtk it calls good old xlib message to pop up a message; I haven't looked at why.
the code is
warn() { echo "$@"
case x"$GUI" in x1) xmessage -center " Winetricks error: $@ " ;; *) ;; esac }
i.e. we haven't bothered to use the nicer dialog for errors. Think we should?