diff --git a/scheme/httpd/cgi-server.scm b/scheme/httpd/cgi-server.scm
index 045f08d..b3985b2 100644
--- a/scheme/httpd/cgi-server.scm
+++ b/scheme/httpd/cgi-server.scm
@@ -128,7 +128,15 @@
 		   (format #f "Could not execute CGI script ~a." 
 			   filename)) 
 		  stat))		;; FIXME! must return http-response object!
-	    (cgi-make-response (run/port* doit) req)))
+	    (case (file-not-executable? filename)
+	      ((search-denied permission)
+	       (make-http-error-response http-status/forbidden req
+					 "Permission denied."))
+	      ((no-directory nonexistent)
+	       (make-http-error-response http-status/not-found req
+					 "File or directory doesn't exist."))
+	      (else
+	       (cgi-make-response (run/port* doit) req)))))
        
        (else (make-http-error-response http-status/method-not-allowed req))))))