Screenlock stops working after reboot. Help!

So I thought I had this issue figured out, but I guess not. Basically, if I do a reboot on my machine (running 10.5.1) the screensaver password stops working. Here's how I can fix it:

If I delete "~/Library/Preferences/ByHost/com.apple.screensaver.WHATEVER.plist" and then go back into the system preferences and select "security" and check the box "require password to wake this computer" and then log out and back in again, it works great. No problems at all.

But, once I reboot the machine it stops working again, even though the box is still checked. Even if I uncheck the box and recheck it, NOTHING. The only way to fix it is to delete that file and log out/in again.

Is it possible that the files is somehow getting corrupt when I reboot? Is there a way to protect that file? I tried changing the owner to root (thinking that maybe it'd prevent me from writing to it), but that didn't work. But I can say that it's SOMETHING WITH THAT FILE that's causing this issue.

Can anyone help?? Any ideas or suggestions?? PLEASE! Thanks for your time.

Actually, upon further inspection, there is no need for me to delete the com.apple.screensaver.HASH.plist file. The screenlock only doesn't work immediately after a reboot. If I logout and log back in again (after rebooting), the screenlock works again. Is it possible that the file isn't being read upon startup...but it is being read upon logging in? Any thoughts?