I got the same problem, I change the file permission and now it can't be turn it back on. I think it has to login as root to change it, but I don't know how.
Hey, sorry i'm not sure how to help.
I couldn't figure it out and plugged the phone back into iTunes and successfully restored to its default factory settings.
I ended up taking my phone to the mall to have them unlock it. unfortunatley they put on OS 4 tho which is pretty much useless.
best of luck