Mystery of the Missing Blocks

[Ranko37]

Good Evening!

I just bought a new server space, and wanted to transfer our existed world over to it. I copied the mod, coremod, config, lib, and world files to this new server. It runs the world fine - except that any previously placed, non-vanilla blocks are missing! They can be placed on the server without issue... but where did all the old stuff go?

Thanks!