Multiple dimensions in MCPC+

[Teraku]

I've been running a Tekkit server for a while now using MCPC+ for a few Bukkit plugins and multiworld support, and I've noticed that player clients sometimes crash when using MystCraft or Dimensional Doors to go from one world to another. This mostly happens when the server has started and people first try to use a portal. When using Bukkit plugins to teleport, everything works correctly.

Here's a relevant part of the crash log. I couldn't get the whole thing.

I think this is due to how MCPC+ doesn't assign fixed dimension ID's to Bukkit worlds, so is there any way to assign them anyway?

Any help would be greatly appreciated.