Maybe this 1.4.7 legacy branch of MCPC+ will fix it. I'll test it out and let you know.
Edit: Crashes fixed and no errors are reported in the console from players entering doors! However, the dimensions generated are still empty, dropping players into the void and sending them to spawn, instead of Limbo.
In addition, throwing items in still causes crashes. I'll report this to the MCPC github and hope someone can find a solution.