There is a known bug for RubyGems 0.8.4 (the latest release) which breaks the FXRuby Gem files. For a description of the problem, see the associated bug (at http://rubyforge.org/tracker/index.php?func=detail&aid=1379&group_id=126&atid=575). A patch to correct this problem has been applied to the latest development version of RubyGems, but until that code is officially released users may wish to use the non-Gem installation methods for FXRuby (namely, the source tarball or the one-click installer). Thanks in advance for your patience while this problem is resolved.