I tried loading up the latest version of the mod but ran into this error:

Here is the log: https://pastebin.com/S5FWYUW6

And here is my mod list:

Horizontal Panes
Additional Bars
Absent by Design
Additional Lights
Ambient Sounds 4
Animal Tamer
Anvil Restoration
Aquaculture 2
Better Azaleas
Bigger Caves
Biomes o Plenty
Blocky Doors
Builders Additions
Clumps
Collective
Comforts
Corail Woodcutter
Craftable Saddle
Croptopia
Curios
Customizable Elytra
Designer Modelling
Ding
[[Extended Slabs]]
Floral Enchantment
Gobber 2
Horse stats mod
Iron chest
JEI
Journey Map
Just Mob Heads
Lantern Colours
Macaws doors, fences, lights, paintings and windows
more villagers
mouse tweaks
optiforge
packed up
rgb blocks
searchlight
spark
starter kit
terraria paintings
the one probe
corail tombstone
toolbelt
tree harvester
vanilla tweaks
water strainer

Not sure if it's a mod incompatibility or something else?

Seems to be my bad porting from the 1.16 version of the mod.
I will fix this eventually of course.
It could also be caused by the changes of forge 1.17 since I made it, which of course I will also fix.

Moral of the story: Either an error from me porting the bop support to 1.17 or forge 1.17 changed something since then.
I assume it hasn't always launched like this as a few hundred people have downloaded it and this is the first bug report.

Thank you for the Report