After adding Minfactory Reloaded to my DW20 pack, I got the following message:
Forge Mod Loader has found world ID mismatches
ID 102 is mismatched. World:(ModID: Minecraft, type amp, ordinal 1) Game (ModID: MFReloaded, type blockVanillaGlassPane, ordinal 0)
ID 79 is mismatched. World: (ModID...