I've tried using all the config files posted over the last two months in this forum but when I reload, every last one of them returns with "The configuration file contains an error and has been replaced with a default config".  I even tried changing just one or two sections in the default and get the same message.  I've even searched for "unprintable" characters and none exist.

Here's one of the files I used from this forum. I don't see anything amiss.

{
  "Permission": "quicksmelt.use",
  "Use Permission": false,
  "Speed Multipliers": {
    "furnace": 1000.0,
    "furnace.large": 1000.0,
    "refinery_small_deployed": 1000.0,
    "campfire": 50.0,
    "skull_fire_pit": 50.0,
    "fireplace.deployed": 50.0,
    "bbq.deployed": 50.0
  },
 "Fuel Usage Speed Multipliers": {
    "furnace": 0.1,
    "furnace.large": 0.1,
    "refinery_small_deployed": 0.01,
    "campfire": 0.01,
    "skull_fire_pit": 0.1,
    "fireplace.deployed": 0.01,
    "bbq.deployed": 0.01
  },​
  "Fuel Usage Multipliers": {
    "furnace": 1,
    "furnace.large": 1,
    "refinery_small_deployed": 1,
    "campfire": 1,
    "skull_fire_pit": 1,
    "fireplace.deployed": 1,
    "bbq.deployed": 1
  },
  "Output Multipliers": {
    "furnace": {
      "metal.fragments": 1.0,
      "sulfur": 1.0,
      "charcoal": 10.0,
      "metal.refined": 1.0
    },
    "furnace.large": {
      "metal.fragments": 1.0,
      "sulfur": 1.0,
      "charcoal": 10.0,
      "metal.refined": 1.0
    },
    "refinery_small_deployed": {
      "lowgradefuel": 1.0
    },
    "campfire": {
      "bearmeat.cooked": 1.0,
      "chicken.cooked": 1.0,
      "deermeat.cooked": 1.0,
      "fish.cooked": 1.0,
      "horsemeat.cooked": 1.0,
      "humanmeat.cooked": 1.0,
      "meat.pork.cooked": 1.0,
      "wolfmeat.cooked": 1.0
    },
    "skull_fire_pit": {
      "bearmeat.cooked": 1.0,
      "chicken.cooked": 1.0,
      "deermeat.cooked": 1.0,
      "fish.cooked": 1.0,
      "metal.refined": 1.0,
      "horsemeat.cooked": 1.0,
      "humanmeat.cooked": 1.0,
      "meat.pork.cooked": 1.0,
      "wolfmeat.cooked": 1.0
    },
    "fireplace.deployed": {
      "bearmeat.cooked": 1.0,
      "chicken.cooked": 1.0,
      "deermeat.cooked": 1.0,
      "fish.cooked": 1.0,
      "metal.fragments": 1.0,
      "horsemeat.cooked": 1.0,
      "humanmeat.cooked": 1.0,
      "meat.pork.cooked": 1.0,
      "wolfmeat.cooked": 1.0
    },
    "bbq.deployed": {
      "bearmeat.cooked": 1.0,
      "chicken.cooked": 1.0,
      "deermeat.cooked": 1.0,
      "fish.cooked": 1.0,
      "sulfur": 1.0,
      "horsemeat.cooked": 1.0,
      "humanmeat.cooked": 1.0,
      "meat.pork.cooked": 1.0,
      "wolfmeat.cooked": 1.0
    }
  },
  "Whitelist": {
    "furnace": [
      "metal.ore",
      "sulfur.ore",
      "hq.metal.ore",
      "can.tuna.empty",
      "can.beans.empty",
      "bearmeat",
      "chicken.raw",
      "deermeat.raw",
      "fish.raw",
      "horsemeat.raw",
      "humanmeat.raw",
      "meat.boar",
      "charcoal",
      "wolfmeat.raw",
      "crude.oil"
    ],
    "furnace.large": [
      "metal.ore",
      "sulfur.ore",
      "hq.metal.ore",
      "bearmeat",
      "chicken.raw",
      "deermeat.raw",
      "fish.raw",
      "horsemeat.raw",
      "humanmeat.raw",
      "meat.boar",
      "wolfmeat.raw",
      "can.tuna.empty",
      "can.beans.empty",
      "crude.oil"
    ],
    "small.oil.refinery": [
      "crude.oil"
    ],
    "campfire": [
      "bearmeat",
      "chicken.raw",
      "deermeat.raw",
      "fish.raw",
      "horsemeat.raw",
      "humanmeat.raw",
      "meat.boar",
      "wolfmeat.raw",
      "can.tuna.empty",
      "can.beans.empty"
    ],
    "skull_fire_pit": [
      "bearmeat",
      "chicken.raw",
      "deermeat.raw",
      "fish.raw",
      "hq.metal.ore",
      "horsemeat.raw",
      "humanmeat.raw",
      "meat.boar",
      "wolfmeat.raw",
      "can.tuna.empty",
      "can.beans.empty"
    ],
    "fireplace.deployed": [
      "bearmeat",
      "chicken.raw",
      "deermeat.raw",
      "fish.raw",
      "metal.ore",
      "horsemeat.raw",
      "humanmeat.raw",
      "meat.boar",
      "wolfmeat.raw",
      "can.tuna.empty",
      "can.beans.empty"
    ],
    "bbq.deployed": [
      "bearmeat",
      "chicken.raw",
      "deermeat.raw",
      "fish.raw",
      "horsemeat.raw",
      "sulfur.ore",
      "humanmeat.raw",
      "meat.boar",
      "wolfmeat.raw",
      "can.tuna.empty",
      "can.beans.empty"
    ]
  },
  "Blacklist": {
    "global": [
      "bearmeat.cooked",
      "chicken.cooked",
      "deermeat.cooked",
      "fish.cooked",
      "horsemeat.cooked",
      "humanmeat.cooked",
      "meat.pork.cooked",
      "wolfmeat.cooked"
    ]
  },
  "Smelting Frequencies (Smelt items every N smelting ticks)": {
    "global": 1
  },
  "Debug": false
}​

Make sure you are using the latest version. Try using JSON validators (search in Google/etc).

Your example above has a few hidden symbols/spaces that are not really valid JSON; I'd suggest checking against http://www.jsonlint.com for validity.

Thanks!  Looks like that did it!