diff --git a/Zend/zend_builtin_functions.c b/Zend/zend_builtin_functions.c
index baeae401ef2..82281c60a92 100644
--- a/Zend/zend_builtin_functions.c
+++ b/Zend/zend_builtin_functions.c
@@ -968,7 +968,7 @@ ZEND_FUNCTION(set_error_handler)
 {
 	zval **error_handler;
 	zend_bool had_orig_error_handler=0;
-	char *error_handler_name;
+	char *error_handler_name = NULL;
  
 	if (ZEND_NUM_ARGS()!=1 || zend_get_parameters_ex(1, &error_handler)==FAILURE) {
 		ZEND_WRONG_PARAM_COUNT();
@@ -976,7 +976,7 @@ ZEND_FUNCTION(set_error_handler)
 
 	if (!zend_is_callable(*error_handler, 0, &error_handler_name)) {
 		zend_error(E_WARNING, "%s() expects the argument (%s) to be a valid callback",
-				   get_active_function_name(TSRMLS_C), error_handler_name);
+				   get_active_function_name(TSRMLS_C), error_handler_name?error_handler_name:"unknown");
 		efree(error_handler_name);
 		return;
 	}