This is a problem mostly on OS X and laptops which frequently go into sleep mode, and the network connection between Guiserver and the application gets lost.
This can be fixed by replacing in /usr/share/newlisp/guiserver.lsp or in c:Program Filesnewlispguiserver.lsp line 1632 (based on 9.2.4):
; replace with
(define (init (portIn 47011) (host "127.0.0.1"))
In non-english versions of Windows "Program Files" may have a localized name.
On Mac OSX and other UNIX use the sudo command to edit the file with administrator permissions.
Lutz