Motif 2.1 or higher is required to run LispWorks with the Motif GUI.
The Motif libraries are installed as part of the SUNWmfrun package. It is usually preinstalled on Solaris 10 and is available for download from Sun for OpenSolaris.
You will also need Imlib (not Imlib2). Imlib version 1.9.13 or later is recommended. Contact Lisp Support if you need this.