The plugin used to store data under its data folder (data/KDRGui) so that players would keep their KDR information persistently. It appears that the plugin no longer stores data.

{
  "id": SteamID,
  "name": "PlayerName",
  "kills": 6,
  "deaths": 2
}​

I'm not currently having any issues with KDRGui. Did you modify the plugin in any way?

Actually, I had two players say it wasn't working, but I tested it seems to work. Nvm, should have tested it myself before posting.