From what I see (unless the pack author has for some reason renamed the jar file), the version I see on the Github for Minechem is 5.0.5.358 and the one in the mod pack is 5.0.5.364, making it a later version...
Unless you're referring to the unstable builds?
Hmmm.... Yes I am. My mistake. I downloaded the unstable build 5.0.5.380 and it worked fine for me. I some times get crashes when nei tries to look up certain decomposer recipes, but I think that bug is also in .364 and its a small price to pay for a working journal and the decomposer accepting fluids.
Anyways, my point is that the problem has already been reported on and dealt with for future builds, rendering reporting the bug again obsolete.