I have an atrix Motorola and I tried to load the "rider x" app (memory problem)

I have a Motorola Atrix and have most all my apps loaded on the sd card. Seems like I can not get "Rider X" app to work. It loads but then won't open. I uninstalled and reloaded. Sometime I get the message - The location Google Play Store (process com.android.vending) has stopped unexpectedly. Please try again. How can I get more internal memory or whatever it is that I need to do? Thanks