This exact same thing happened to me. Server was running find until I installed ZomBerry, and the large tent backpack was what crashed me as well. The item didnt show up, but mousing over it said it was there. I could even pick up the invisible large tent backpack...but as soon as I hit tab to look at my inventory, it crashed the game and shut everything down. I couldnt resolve it, so ended up having to wipe my server and rebuild it.

There are 2 options for solving it with any item:
- If it's on the ground, set item lifetime to a few seconds in types.xml (or just delete it from the world using mod functionality)
- If it's in your inventory, either wipe your inventory or, uhh, dispose of your character in other ways

If you want to report items that should be moved to Expert catergory, please include item class name. If you've spawned something hidden by default by switching to Expert mode - there's not much I can do about it. It literally includes every single spawnable object in the game, going over every single one and testing circumstances under which these items crash the game would take a considerable amount of time