Screensaver Getting Suck on Script

I am trying to make a script for a login item that will engage my screensaver on login. I have it set to ask for a password on wake from sleep or screensaver so I’m using this to lock it on login (This is cause I want it to autologin and play an itunes song and yet still be secure while i’m away). I am currently using the code

do shell script "/System/Library/Frameworks/ScreenSaver.framework/Resources/ &"

The problem is, when i wake it from the screensaver, it doesn’t ask for a password and just gets stuck with a black screen and the cursor. Is there any way to make it ask for the password and close the screensaver like normal?