I have 2.1 installed on my 2g iphone and I just wanna see how passcode will work. Now, I want to disable it but when I hit "Passcode lock" under settings, settings window crash and returns to main menu.
Give it a hard reset (home and top button until it goes off and restart it). If that doesn't work, I would recommend you uninstall somethings and make sure nothing is running in the background then try again.