Also in Factorio 1.1 the same problem :)

44.568 Loading mod beltlayer 1.1.0 (data-updates.lua)
44.630 Error ModManager.cpp:1555: Fehler beim Laden der Mod „beltlayer“: beltlayer/prototypes/bpproxies.lua:109: attempt to index local 'layers' (a nil value)
stack traceback:
beltlayer/prototypes/bpproxies.lua:109: in function 'make_underground_belt_sprites'
beltlayer/prototypes/bpproxies.lua:133: in function 'make_underground_belt_proxies'
beltlayer/prototypes/bpproxies.lua:142: in main chunk
[C]: in function 'require'
beltlayer/data-updates.lua:2: in main chunk

List of mods used: https://mods.factorio.com/mod/multiplayer_extreme_modpack/downloads

I cannot install this modpack because one of its dependencies is not on the mod portal.

I will check it

@therax
Fixed now, thanks for the information, download should now possible without problems :)

Fixed a conflict with Yuoki Engines.

@therax
works! Thank you very much :)