HttpClient report no memory

Hi, i am new to Cocos2dx and i think this engine is awesome, it helped me a lot.

But recently, i met a problem when i was using HttpClient. It always reports no memory when I am trying to send any request, even if I copy the sample codes from HttpClient test to my project.
Because i am using Visual Leak Detector to detect any memory leak problem, so if i turn off this tool and send request again, no memory problem never happens again.

Could anyone tell me why? Is it my problem, Visual Leak Detector problem or engine’s problem. Thanks