The recipe for Plutonium Cells (1 Uranium Cell + 1 UU Matter) doesn't seem to be craft-able in SMP both config files of client and server match exactly. In singleplayer the recipe works perfectly.
In SMP upon placing both materials in the crafting grid the plutonium cell shows up. But trying to grab the plutonium cell to complete the craft results in the crafting grid items disappearing and reappearing within a second and you ending up without the plutonium cell.
Are really ALL the Configs identical? (Massfabricationrate and Massfabdisabling especially)
These are manipulating the costs of UUM for Plutonium.