Today Apple released update 10.8.2 for Mountain Lion. It fixes the problem that forced IP Camera Viewer to disconnect from some cameras.

Now you can continue monitoring IP Cameras on your Mac.
To update your Mac: choose Apple menu > Software Update … or see http://support.apple.com/kb/HT5460

Do not forget: we now have an easy to use, advanced video surveillance software for your Mac. It lets you record video on your Mac and access it from anywhere, even from your iPhone. Check out our IP Camera Recorder for Mac