--- a/main/pbx.c	2012-07-10 15:33:53.000000000 +0200
+++ b/main/pbx.c	2012-10-30 15:40:28.322741680 +0200
@@ -6878,14 +6878,14 @@
 
 	manager_show_dialplan_helper(s, m, idtext, context, exten, &counters, NULL);
 
-	if (context && !counters.context_existence) {
+	if (!ast_strlen_zero(context) && !counters.context_existence) {
 		char errorbuf[BUFSIZ];
 
 		snprintf(errorbuf, sizeof(errorbuf), "Did not find context %s", context);
 		astman_send_error(s, m, errorbuf);
 		return 0;
 	}
-	if (exten && !counters.extension_existence) {
+	if (!ast_strlen_zero(exten) && !counters.extension_existence) {
 		char errorbuf[BUFSIZ];
 
 		if (context)