BSD systems

FreeBSD

The filer is in FreeBSD's ports collection:
httphttp://www.freebsd.org/cgi/url.cgi?ports/x11-fm/rox-filer/pkg-descr
Warning: the FreeBSD port does CHARSET=iso-8859-1 before running the filer, which prevents it from working in other locales.
See httpthis thread for details.

NetBSD

The filer is in NetBSD's pkgsrc collection at:
/usr/pkgsrc/sysutils/rox/

See also:
httpftp://ftp.netbsd.org/pub/NetBSD/packages/pkgsrc/sysutils/rox/README.html

OpenBSD

The filer is in OpenBSD's ports collection at:
/usr/ports/x11/rox-filer
And also as a package from the FTP mirrors:
httphttp://www.openbsd.org/ftp.html