I can not be of much help to you, this has happened to me a couple of different times. I found no fix for this scenario, I ended up doing a reinstall.
Try doing a google search with "sudoers is owned by uid 1000, should be 0" and see what you come up with. Also search these forums for "sudoers"
If you do find a fix that works, please post back here so other users can benefit from it. Good luck.......
My Linux Distros:
sidux - Parsix - DreamLinux - Mint