Not sure about the reader app since I don't use it but the latest youtube app works for me. Maybe try uninstalling and reinstalling. I also noticed that the market sometimes doesn't list apps I KNOW are available and can clearly find using my droidx so I have had to result to finding and downloading them as an apk off the web. I.e. google music app said wasn't compatible with the Coby but found it on the interwebs and it runs just fine on the tablet.