Cydia not opening on an iTouch (2nd gen) v4.2.1?

I have an iTouch (2nd gen) v4.2.1 that is in the process of being jailbroken. I used greenpois0n, then used the Loader App to install Cydia. Now, it will open Cydia, and say "Initializing filesystem, Cydia will exit when complete", then return me to where I have to slide to unlock.