I would have to agree with Kuboman. If its the plug holes themselves then I would attempt the tap for that size hole and then "slowly" start running the plugs back in. Say like 3 turns forward one turn back to make sure you're not re-striping them. Try that before a time-sert kit. Easier for the first try. Might be a good idea to get new drain plugs too if the current ones look at all damaged.
Also, if you haven't tapped a hole before, I know that sounds funny, you need to do it in the same manner. But, use half turns. Thread it in just a little and then back. Then a bit more and back again. If there is no residual oil in the pan then maybe put some on the hole threads first or continue to spray some WD40 on there to keep the tap lubed in the hole. Couldn't resist that last one. Good luck.