Title: Items appear momentarily when crafted then disappear.
Version: 3.1.1
OS: Mac OS X 10.6.8
Java Version: 1.6.0_29
Description of Problem:
Whenever I try to craft an item, the item will appear in the outcome section of the crafting table then disappear almost instantly. I've tried restarting and re-logging. I should mention that this is in multiplayer. The server is running off of a computer with the same specs as mine. My brother is also connected to the server and he can't craft items either. This seems to only be happening with Tekkit related items as we can craft all the regular Minecraft Vanilla items.
Error Messages:
Error Log: