Failed to load mods: dectorio-fixes/prototypes/third-party/other.lua:15: attempt to index field 'dect-stone-brick-wall' (a nil value)
stack traceback:
dectorio-fixes/prototypes/third-party/other.lua:15: in main chunk
[C]: in function 'require'
dectorio-fixes/data.lua:56: in main chunk

Post your mod list.
As it loads fine standalone, and with some mods i tested it when i made it.

Here you go, there's a lot though lol.

https://puu.sh/KIkRY/5a6b610579.txt

On the crash popup, click to reset the mods settings and restart. Worked for me.

only happens when the config to turn off wall/gates is on

other.lua

if mods["aai-industry"] then
    data.raw.wall["dect-simple-concrete-wall"] = nil
    data.raw.item["dect-simple-concrete-wall"] = nil
    data.raw.recipe["dect-simple-concrete-wall"] = nil
    data.raw.recipe["dect-concrete-wall-from-stone-wall"] = nil
    data.raw.gate["dect-simple-concrete-gate"] = nil
    data.raw.item["dect-simple-concrete-gate"] = nil
    data.raw.recipe["dect-simple-concrete-gate"] = nil
    data.raw.recipe["dect-concrete-gate-from-stone-gate"] = nil
else
    if settings.startup["dectorio-walls"] and settings.startup["dectorio-walls"].value then
        data.raw.recipe["stone-wall"].hidden = true
        data.raw.item["stone-wall"].hidden = true
        data.raw.recipe["gate"].hidden = true
        data.raw.item["gate"].hidden = true
        data.raw.wall["dect-stone-brick-wall"].localised_name = { "entity-name.stone-wall" }
        data.raw.gate["dect-stone-brick-gate"].localised_name = { "entity-name.gate" }
        for k, v in pairs(data.raw.technology["stone-wall"].effects) do
            if v.recipe == "stone-wall" then v.recipe = "dect-stone-brick-wall" end
        end
        for k, v in pairs(data.raw.technology["gate"].effects) do
            if v.recipe == "gate" then v.recipe = "dect-stone-brick-gate" end
        end
    end
end

if mods["AsphaltRoadsPatched"] then
    data.raw["item-subgroup"]["Arci-asphalt-1"].group = "dectorio"
    data.raw["item-subgroup"]["Arci-asphalt-1"].order = "i-r"
    data.raw["item-subgroup"]["Arci-asphalt-2"].group = "dectorio"
    data.raw["item-subgroup"]["Arci-asphalt-2"].order = "i-r"
    data.raw["item-subgroup"]["Arci-asphalt-3"].group = "dectorio"
    data.raw["item-subgroup"]["Arci-asphalt-3"].order = "i-r"
end

if mods["space-exploration"] then
    data.raw["item-subgroup"]["landfill"].group = "dectorio"
    data.raw["item-subgroup"]["landfill"].order = "l-b"
end

Wrapping the else block in an if-then, checking if Walls and Gates is enabled, seems to work for me.

I just ran into this bug as well (I also had walls and gates disabled in my save). It would be great to have this fixed and rolled into the 2.1 update.

(fixed in 0.13.3 for 2.0 and in 0.13.4 for 2.1)