Hello, here's directions for an older OSX version, not on 10.7 to see if locations of the files have changed...
Safe Boot , (holding Shift key down at bootup), use Disk Utility from there to Repair Permissions, move these files to the Desktop if they exist. Will require resetting some options.
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.
Oh, are other things remaining after a reboot, like Dock Settings & Bookmarks?