as per my reading of the Hyperspec (http://clhs.lisp.se/Body/f_logica.htm), CL:LOGICAL-PATHNAME-TRANSLATIONS should signal a TYPE-ERROR if an unknown logical host name is specified as argument. CLISP signals a SIMPLE-ERROR instead.
thank you for your bug report.
the bug has been fixed in the source tree (mercurial/hg).
you can either wait for the next release (recommended)
or check out the current mercurial tree (see http://clisp.org\)
and build CLISP from the sources (be advised that between
releases the source tree is very unstable and may not even build
on your platform).