This happens on my modpack when asking for a molten metal's usage in NEI.
I think the crash report says it all.

Report:
http://pastebin.com/R78JANf7

Additional note: I think this hurries the need for mod support. At least for the ore dictionnary.

I haven't seen much how the NEI plugin or the alchemy recipe handler works yet, but I guess it's time for that now.
EDIT: Oh, I mean the CombinationRegistry (and maybe also GristRegistry), not AlchemyRecipeHandler.