Pretty much what it says on the tin, error code below:

Failed to load mods: flib/data-util.lua:18: attempt to index local 'prototype' (a nil value)
stack traceback:
flib/data-util.lua:18: in function 'copy_prototype'
double-inserter/data-final-fixes.lua:139: in main chunk

Mods to be disabled:
• double-inserter (2.2.2)

What mods do you have installed?

all loaded mods (except multi inserters)
{
BuggisNuclearBots = "2.0.1",
CleanFloor = "2.0.0",
DiscoScience = "2.0.1",
["Explosive Termites"] = "1.1.16",
FNEI = "0.4.6",
LabDansen = "0.2.0",
Milestones = "1.4.7",
QualityAssurance = "1.4.4",
RPGsystem = "2.0.7",
StackInsertersForBobs = "0.1.5",
SteeperQuality = "1.0.2",
["Todo-List"] = "19.14.1",
["aai-containers"] = "0.3.2",
["aai-signal-transmission"] = "0.5.3",
["alien-biomes"] = "0.7.4",
["alien-biomes-graphics"] = "0.7.1",
["angelsaddons-bots"] = "2.0.0",
["angelsaddons-cab"] = "2.0.0",
["angelsaddons-mobility"] = "2.0.1",
["angelsaddons-mobility-graphics-crawler"] = "2.0.0",
["angelsaddons-mobility-graphics-petro"] = "2.0.0",
["angelsaddons-mobility-graphics-smelting"] = "2.0.0",
["angelsaddons-storage"] = "2.0.1",
angelsbioprocessing = "2.0.2",
angelsbioprocessinggraphics = "2.0.0",
angelspetrochem = "2.0.1",
angelspetrochemgraphics = "2.0.1",
angelsrefining = "2.0.2",
angelsrefininggraphics = "2.0.0",
angelssmelting = "2.0.2",
angelssmeltinggraphics = "2.0.0",
base = "2.0.72",
["blueprint-sandboxes"] = "3.2.2",
bobassembly = "2.0.5",
bobelectronics = "2.0.5",
bobenemies = "2.0.4",
bobequipment = "2.0.3",
bobgreenhouse = "2.0.3",
bobinserters = "2.0.3",
boblibrary = "2.0.3",
boblogistics = "2.0.6",
bobmining = "2.0.4",
bobmodules = "2.0.6",
bobores = "2.0.3",
bobplates = "2.0.5",
bobpower = "2.0.4",
bobrevamp = "2.0.5",
bobtech = "2.0.5",
bobvehicleequipment = "2.0.4",
bobwarfare = "2.0.5",
["companion-drones-mjlfix"] = "3.1.2",
["elevated-rails"] = "2.0.72",
factoryplanner = "2.0.43",
flib = "0.16.5",
["gear-girl"] = "1.1.2",
["kilroys-advanced-radars"] = "0.9.0",
["mech-armor"] = "1.0.1",
["more-quality-scaling"] = "1.4.11",
qol_research = "3.4.2",
quality = "2.0.72",
["reskins-angels"] = "2.3.3",
["reskins-bobs"] = "2.3.6",
["reskins-compatibility"] = "2.3.9",
["reskins-library"] = "2.3.3",
["roboport-charging-pads-count-quality"] = "0.0.2",
["skins-factored"] = "1.3.5",
["squeak-through-2"] = "0.1.3",
["stacked-scrap-results"] = "2.1.1",
["vanilla-loaders-hd"] = "2.2.2"
}

I'll give it a look! Any chance you can provide the log file when trying to load it with the mod? I only need the last little bit of the file

12.574 Script @double-inserter/data-final-fixes.lua:138: double-inserter: copying inserter prototype 'bob-express-bulk-inserter' -> 'sex_bob-express-bulk-inserter'
12.575 Script @double-inserter/data-final-fixes.lua:138: double-inserter: copying inserter prototype 'bob-express-bulk-inserter' -> 'sep_bob-express-bulk-inserter'
12.576 Script @double-inserter/data-final-fixes.lua:138: double-inserter: copying inserter prototype 'bob-express-bulk-inserter' -> 'oct_bob-express-bulk-inserter'
12.577 Script @double-inserter/data-final-fixes.lua:138: double-inserter: copying inserter prototype 'bob-red-inserter' -> 'double_bob-red-inserter'
12.577 Error ModManager.cpp:1764: Failed to load mod "double-inserter": flib/data-util.lua:18: attempt to index local 'prototype' (a nil value)
stack traceback:
flib/data-util.lua:18: in function 'copy_prototype'
double-inserter/data-final-fixes.lua:139: in main chunk
12.613 Loading mod core 0.0.0 (data.lua)
12.784 Checksum for core: 3810281447
12.811 Error ModManager.cpp:1764: Error in assignID: recipe-category with name 'recycling' does not exist.

Source: default (utility-constants).
12.819 Info PlayerData.cpp:66: Local player-data.json unavailable
12.819 Info PlayerData.cpp:69: Cloud player-data.json available, timestamp 1769022012
12.821 Post-data load graphics options: [Light occlusion: no]
13.260 Initial atlas bitmap size is 8192
13.261 Created an atlas bitmap (size 4096x496) [icon, not-compressed, mipmap, linear-minification, linear-magnification, linear-mip-level]
13.261 Loading 3D bitmaps.
13.275 Texture processor created (4096). GPU accelerated compression Supported: yes, Enabled: yes/yes. Test passed. YCoCgDXT PSNR: 35.83, BC3 PSNR: 33.82
13.276 Parallel sprite loader initialized (threads: 3, bitmaps: 146)
13.352 Sprites loaded
13.364 Generated mipmaps (5) for atlas [0] of size 4096x496
13.365 Custom mipmaps uploaded (117)
13.422 Video memory usage: 10.32 MB (Atlases: 10.32 MB, Textures: 0.00 MB)
13.426 Factorio initialised
13.431 Failed to load mods: flib/data-util.lua:18: attempt to index local 'prototype' (a nil value)
stack traceback:
flib/data-util.lua:18: in function 'copy_prototype'
double-inserter/data-final-fixes.lua:139: in main chunk

Mods to be disabled:
• double-inserter (2.2.2)

Thanks! That's immensely helpful!