This tool is very old, and I don't even have the source code of my old NBT library which I used in this project. I don't want to, and also can't update NBTedit to add support for the new int tag which was added to Minecraft a while ago. There's a few other tools linked at the bottom of this post which might be helpful (I suggest NBTExplorer), and if you find / made any I'd be glad to link them.
Other helpful tools you may want to check out:
- NBTExplorer: A better NBT editor by jaquadro.
- In-Game NBTEdit: Forge compatible mod for editing (tile) entities by Davidee.
- INVedit: Inventory editor by me.
- Not Enough Items: Inventory editor mod and more by ChickenBones.
- Too Many Items: Inventory editor mod by Marglyph.
- MCEdit: World editor by codewarrior.