Index: request.c
===================================================================
--- request.c	(revision 5446)
+++ request.c	(working copy)
@@ -118,7 +118,8 @@
 
       ippDelete(request);
 
-      _cupsSetError(IPP_NOT_POSSIBLE, NULL);
+      snprintf(buffer, sizeof(buffer), "\"%s\" %s", filename, strerror(EISDIR));
+      _cupsSetError(IPP_NOT_POSSIBLE, buffer);
 
       return (NULL);
     }
