I have used the app before with good results. But, after updating to Android 4 on my phone, I cannot start the app. It says it cannot create root directory and that sd card is "probably missing". I never had to have an sd card before, and I put cartridges in the external_sdwhereyougo folder. Now I see I do not have such a folder after the upgrade, and it will not allow me to create one. Must I go and buy an sd card now that I have android 4?