I'm running CM7 nightly 107 and this wasn't working for me and niether was AdFree. Niether of the apps could write to my SD card. I updated to the latest BusyBox and everything got fixed. Just an idea for folks having trouble.
Or you can install the latest Busybox using the Busybox Installer app with the blue arrow on the icon. The other one with the gears in the icon doesn't work for me.
I use the Crazy on Digital Black Leather Folio Case. It folds into a nice stand in landscape mode for reading and viewing Netflix movies. It cost a wopping $14.99...LOL