diff --git a/scheme/httpd/rman-gateway.scm b/scheme/httpd/rman-gateway.scm
index b32e07d..cacdbc2 100644
--- a/scheme/httpd/rman-gateway.scm
+++ b/scheme/httpd/rman-gateway.scm
@@ -23,7 +23,13 @@
 		     (unescape-uri (http-url-search url))
 		     '())))
 	  (else
-	   (let ((man-path ((infix-splitter ":") (getenv "MANPATH"))))
+	   (let ((man-path 
+		  ((infix-splitter ":") 
+		   (or (getenv "MANPATH")
+		       (begin 
+			 (format (current-error-port)
+				 "~%Warning: environment variable MANPATH is unset.~%")
+			 "")))))
 	     (lambda (url)
 	       (values man-path
 		       (unescape-uri (http-url-search url))