I've ran into this issue a lot with my iPad 2 and my iPhone 4. What is comes down to is that the app is not completely optimal for the iOS yet. This is what I have done to correct it.First, I "delete" the app. You can do this by holding down the NetFlix app on your springboard until it "wiggles". When it wiggles, press the X and agree to delete the app and its data.Once it is deleted, hold the Home and Power buttons at the same time until your iPad goes completely black. Wait 15 seconds. Then hold the Power down until you see the Apple Logo.After your iPad boots up, go to Settings -> General -> Reset -> Reset Network Settings (this will wipe any WiFi passcodes or security keys that are saved to the device, but will clear the cache of the Netflix information). After this completes your iPad will reboot.Upon reboot, go to Settings -> Safari -> press all the Clear options listed.From there, go back to Settings -> General -> Reset -> Reset Network Settings.After your iPad reboots, reconnect to your WiFi (or 3G if you have it) and then go to App Store, and redownload/reinstall the Netflix app.After it installs, hold the Home and Power buttons at the same time until your iPad goes completely black. Wait 15 seconds. Then hold the Power down until you see the Apple Logo.After your iPad boots up, open Netflix, log in, and see if it works.If it doesn't, try a different WiFi spot (or if on 3G, get on a WiFi spot) and then reboot the device and attempt to log in.If it still doesn't work, the Netflix portal for the iOS device might just have an issue, you might need to just wait it out.
Okay "white screen/loading" usually means that your device isn't connecting stabling to the WiFi connection.Do the Power/Home button hold down reboot method, move closer to the WiFi router, and then attempt the App Store again.If that doesn't work, try a different WiFi connection.