Index: gvfs-1.5.4/gconf/gapplookupgconf.c
===================================================================
--- gvfs-1.5.4.orig/gconf/gapplookupgconf.c
+++ gvfs-1.5.4/gconf/gapplookupgconf.c
@@ -107,6 +107,9 @@ get_default_for_uri_scheme (GDesktopAppI
 
   appinfo = NULL;
   
+  if (uri_scheme == NULL || *uri_scheme == '\0')
+    uri_scheme = "unknown";
+
   client = gconf_client_get_default ();
   
   command_key = g_strconcat (GCONF_PATH_PREFIX,