I use LP build 89, Railcraft 3.4.0.0 and NEI 1.0.3.78. When I searched a recipe for a Railcraft's item, it made this crash : http://pastebin.com/qVkHDxDF.

……have you tried update your NEI to 1.0.3.74?

Sorry, I wanted to say 1.0.3.78

Now that one is strange. It says that our static initialiser for the IdemIdentifier class failed to run. That is realy strange because there is nothing out of the ordinary in there.