I downloaded 1.6.1 with the new minecraft launcher, I now went to my test world. The first thing I do is open up my Test World, and then I put a diamond in the chest.. then, I went to MCEDIT and used Sethbling's filter to make attributes.. I think I put one of my percentages too high, which is +%3333333 Knockback Resistance and I also modified the item strings to "§9Unholy Diamond".. once I got into my Test World, I opened up the chest with the diamond, I put my cursor on it. My Minecraft had died. I tried a few times to at least get it out, it still died. So, I thought of an idea.. I destroyed the chest with the diamond, but the diamond had fell on me and I accidentally picked it up. Now my Minecraft died again.. and now, whenever I go into my test world, I just crash! So, please fix this..