IStrings won't work for iPhone 3G 4.2.1?

My iPhone 3G is Jailbroken, and I heard some 4.2.1's iStrings app won't work. I have winterboard and I tried it with it on and off, I clicked apply, and it still wouldn't show any results. I have a Greenpois0n theme, so instead of the boring original, "Slide to Unlock" I put Slide to pois0n. Still won't work. I also have a custom slider if it helps with the question. I even try to Respring, I did it like about 6 times already, no results. Thanks in advance if I get an answer that really helps me! :)