iPhoneOS4.0 Wifi Scanning problem

I have just started to make a iPhone Wifi scanning app. I have searched a lot websites, finally I have the recent code the below. Someone told this is working for iPhoneOS4.0 well.

libHandle = dlopen("/System/Library/SystemConfiguration/WiFiManager.bundle/WiFiManager", RTLD_LAZY);

open  = dlsym(libHandle, "Apple80211Open");

bind  = dlsym(libHandle, "Apple80211BindToInterface");

close = dlsym(libHandle, "Apple80211Close");

scan  = dlsym(libHandle, "Apple80211Scan");

But, I have the below warnings.

warning: Unable to read symbols for "/Developer/Platforms/iPhoneOS.platform/DeviceSupport/4.0.1/Symbols/usr/开发者_如何学Pythonlib/libpcap.A.dylib" (file not found).

warning: Unable to read symbols for "/Developer/Platforms/iPhoneOS.platform/DeviceSupport/4.0.1/Symbols/System/Library/SystemConfiguration/WiFiManager.bundle/WiFiManager" (file not found).

I am using xcode_3.2.3_and_ios_sdk_4.0.1 and iPhone 3G device that jailbroken, unlocked and updated to 4.0.1.

I know, if I use a private API, can not service and get a risks, but I should do that. If you any clue about this, please let me know.