This has been fixed! Thank you for the prompt help!
Hello! I've been on the Boisonberry server for a couple of days now, and I've been enjoying it... until I broke things.
So. I built my first electric furnace, and threw in a random item (a piece of coal) to see if it was working.
It was! However, my choice of item glitched out the furnace-- every time I tried to open it, I would get a Java null pointer error. Then I knocked down the furnace with my wrench, on my friends' advice. Now the furnace works (they came over to poke at it for me) but I can't log into the server-- I get the error every time I try to load my character, Paksarra.
Based on the information in this thread , I think I know what happened and how to fix my character. Basically, when I cooked the coal it created an item that the game doesn't know how to handle (instead of just not cooking the coal.) When I knocked down the furnace, that item got sucked into my inventory, which is why I can't log in now. If the item were deleted from my inventory, I would be fixed and could log in again. (I had some nice items that were gifted to me-- namely a powered vibro-sword and diamond drill that I can't make myself yet-- but nothing irreplaceable.) My friends can walk around my house, so it's not my location.
I did try another computer; this happens no matter which computer I am on.
Thank you for your time, and for allowing me on your server. :)