I have the same exact problem after the last 1.5.8 update. Playing on Steam/Windows.
After performing a clean install of the latest version, installing all the packs that are listed above, the issue still persisted. So, I opened the game console and found out that the mod loader doesn't load the MoreParts mod.
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Also any other pack that I try to add throws the same error but I guess it must be originating from the MoreParts issue.
I was playing with dani's mod loader until the last update without any problems.
Has anyone found a solution for this ?