When you are taking multiple pictures in a row, iPhone is out of memory processing previous ones. When you are using Objective-C you can add observer with this code:
[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(cameraIsReady:)
name:AVCaptureSessionDidStartRunningNotification object:nil];
However, this API is not implemented in Titanium, so right now to solve this problem you have to catch this error wait couple seconds showing user quick information and then try again.