Is there really no /usr/local/bin/lefty, or is it just that dotty can't find it? Do you have /usr/local/bin in your PATH ?
One other possibility. Lefty will not get build if -lXpm is unavailable (from xorg-x11-libs)
Did you see any warnings during ./configure ?
[gregory.muller] I re-installed xorg-x11-libs-6.7.0-14.i386.rpm and its dependances (by the way I noticed I had made a mistake in the informations I had given you : the architecture of my computer is i386 and not x86.). But I still have the same warnings (see attached file) . ./configure can't find x11... Can you help me ? (as you may have seen, i don't have a great linux knowledge...)
[ellson] Did you install the -devel rpms for xorg-x11 ?
Did I ask why you aren't using the binary rpms?