The various bits of X that deal with font files, do not handle filenames with spaces in them, which causes users grief, especially when dropping in font files from Windows and other OSs which generally use spaces in filenames gratuitously. This is a long standing problem in X11, which is probably very trivial to fix once all the places are isolated. An upstream bug report is tracking this as well: http://bugs.xfree86.org//cgi-bin/bugzilla/show_bug.cgi?id=296 This would be nice to have fixed for the next release of XFree86, and our next OS release.
Deferring for future development
Upstream bug report moved from xfree86.org to freedesktop.org bugzilla. http://freedesktop.org/cgi-bin/bugzilla/show_bug.cgi?id=293