Safe Boot from the HD, (holding Shift key down at bootup), run Disk Utility in Applications>Utilities, then highlight your drive, click on Repair Permissions, then move these files to the Desktop.
(Safe boot may stay on the gray radian for a long time, let it go, it's trying to repair the Hard Drive.)
(Then Trash the original of this one, as "moving" it only copies it.)
Then reboot once more.
PS. Safe boot may stay on the gray radian for a long time, let it go, it's trying to repair the Hard Drive.
EDIT: added a couple of things.
Hi there, thanks for the detailed response! Unfortunately, I still can't get it to work. First of all, when I go to /Library/Preferences/ the com.apple.sharing.firewall.plist file simply isn't there. Is that a problem? hehe Secondly, I did the whole thing excepting the aforementioned file that isn't there, and the problems continue. Could the missing file be the key, or is there another solution? Thanks again for your time and help!